Riyadh Airport Attack: Can the Houthis Legally Target Civilian Airports?

Introduction

The Riyadh airport attack on October 7, 2026, killed a Sudanese national and injured eight others at King Khalid International Airport, according to Saudi Arabia’s General Authority of Civil Aviation. A separate attack on Abha International Airport on October 6 killed two residents and injured 28 people.

Together, the incidents left three people dead and 36 injured, with Yemen’s Houthi movement claiming responsibility for both operations (Anadolu Agency, 2026; Associated Press, 2026). Under international humanitarian law, civilian airports are protected against direct attack unless the particular objects targeted qualify as military objectives.

On October 8, Houthi military spokesman Yahya Saree claimed that a ballistic missile had struck King Khalid International Airport. The Saudi-led coalition reported intercepting two missiles heading toward Riyadh. Reuters subsequently reported, citing three people briefed on the incident, that a parked Saudia aircraft had caught fire and sustained serious damage.

Reuters separately verified footage showing smoke and flames rising from the airport. The available evidence does not conclusively establish whether the Houthi missile directly struck its claimed target or whether interception debris or another projectile caused the reported aircraft damage (Reuters, 2026; Associated Press, 2026).

The attacks disrupted commercial flights, prompting cancellations, airline suspensions, and temporary interruptions to airport operations. Houthi warnings against operating in Saudi airspace have raised concerns about further strikes as fighting intensifies between the group and Saudi-backed Yemeni forces.

The danger extends beyond direct missile impacts. Saudi authorities also reported damage to civilian buildings in Riyadh from falling interception debris. Although the Houthis have threatened additional operations, their statements do not establish when or where another attack might occur (Associated Press, 2026; Reuters, 2026).

The legality of attacking an airport depends on its actual military function and the circumstances of the operation. Under customary international humanitarian law, an object qualifies as a military objective only when it makes an effective contribution to military action and its destruction, capture, or neutralization offers a definite military advantage (Henckaerts and Doswald-Beck, 2005, Rules 7–8).

Even an attack against a legitimate military objective is prohibited if the expected incidental civilian harm would be excessive in relation to the concrete and direct military advantage anticipated. Attackers must also take feasible precautions to minimize civilian harm (Henckaerts and Doswald-Beck, 2005, Rules 14–15).

These customary obligations apply in both international and non-international armed conflicts, although the direct applicability of particular treaty provisions depends on the conflict's classification. The central legal question surrounding the Riyadh attacks is whether the Houthis targeted identifiable military objectives and complied with the restrictions governing the conduct of hostilities.

1. The Riyadh Airport Attack, October 6–8

The attacks on Saudi Arabia's civilian airports unfolded over three consecutive days in October 2026. Abha International Airport was attacked on October 6, followed by King Khalid International Airport in Riyadh on October 7. Saudi aviation authorities reported civilian deaths, injuries, and damage at both facilities, while Yemen's Houthi movement claimed responsibility for the operations (Saudi Gazette, 2026).

The violence continued on October 8, when the Houthis announced another ballistic missile attack against Riyadh. Explosions were reported in the capital, flights were interrupted, and the Saudi-led coalition announced that several incoming missiles had been intercepted. Reuters subsequently reported serious damage to a parked Saudia aircraft at King Khalid International Airport, although the cause of the damage remained uncertain (Azhari and Maccioni, 2026).

The reported incidents involve different forms of evidence. Saudi authorities provided official casualty figures and military statements, while Houthi representatives announced operations that the group claimed to have conducted. Witnesses described explosions and airport evacuations, but those observations did not establish the trajectories or impact points of individual missiles. The available accounts must be distinguished before determining what occurred during each operation.

1.1 The October 7 Attacks and Civilian Casualties

Saudi Arabia's General Authority of Civil Aviation (GACA) reported on October 7 that attacks against Abha International Airport and King Khalid International Airport had killed three people and injured 36. According to the authority, the incidents occurred on October 6 and 7, respectively. Emergency response teams attended both facilities, and the injured were transferred to hospitals for treatment (Saudi Gazette, 2026).

At Abha International Airport, in southwestern Saudi Arabia, two female residents of Moroccan and Algerian nationality were killed. Another 28 people sustained injuries ranging from minor to serious. The casualties included Saudi citizens and foreign residents, among them Bangladeshi and Filipino nationals. GACA also reported material damage, although its public statement did not provide a detailed assessment of the affected infrastructure.

The attack on King Khalid International Airport occurred the following day. A Sudanese resident was killed, while eight other people were injured: five Saudi citizens, two Egyptian residents, and one Pakistani resident. The aviation authority reported property damage and stated that it was coordinating with the relevant agencies to assess the facilities and maintain safe airport operations (Saudi Gazette, 2026).

Houthi military spokesman Yahya Saree claimed that the movement had targeted King Khalid International Airport with drones and Abha International Airport with ballistic missiles and drones. These statements identified the weapons and targets claimed by the group, but did not independently establish which projectiles caused the reported casualties. The Saudi aviation authority confirmed the consequences of the incidents without publishing a comprehensive technical account of the attacks.

The deaths and injuries occurred at facilities ordinarily used by civilian passengers, airline personnel, and airport employees. Their exposure to missile and drone operations demonstrates the immediate danger created by hostilities involving civilian aviation infrastructure. These casualties preceded the renewed missile operations of October 8 and must remain separate from the later reports of explosions and aircraft damage.

1.2 The October 8 Missile Claims and Interceptions

On October 8, Yahya Saree announced that Houthi forces had launched a ballistic missile against King Khalid International Airport and claimed that it struck the intended target. Several explosions were heard in Riyadh, including a substantial blast reported at the airport. An Associated Press witness described smoke, emergency vehicles, and passengers being instructed to evacuate the terminal (Ezzidin and Anna, 2026).

The Saudi-led coalition presented a different account of the missile activity. Its spokesman, Major General Turki al-Maliki, announced that coalition defenses had intercepted and destroyed two ballistic missiles launched toward Riyadh and another directed at Khamis Mushait, near the Yemeni border. The city is located close to a major Saudi military air base.

The coalition's interception claims did not independently resolve the Houthis' assertion that a missile had reached King Khalid International Airport. Nor did the explosions reported by witnesses establish a direct impact. Defensive interceptions can produce explosions and falling fragments, making the distinction between an incoming missile, its interception, and subsequent debris damage particularly significant.

Later on October 8, Saree claimed that Houthi forces had launched additional ballistic and cruise missiles against airports in Riyadh and Najran. The Associated Press reported these announcements but could not independently confirm the operations or their results. The Houthis also repeated warnings to international airlines against operating in Saudi airspace, which the movement characterized as an area of military operations (Ezzidin and Anna, 2026).

Saudi civil defense authorities separately reported that debris from an intercepted ballistic missile had damaged a kindergarten and a medical complex in Riyadh. Their statement did not identify casualties from that incident. The available reporting also did not conclusively connect the debris damage to the particular missile that the Houthis claimed had struck King Khalid International Airport.

The October 8 accounts establish renewed missile activity, explosions, and substantial disruption in the Saudi capital. They do not establish the precise trajectory and impact location of every projectile. A claim that an airport was targeted must also be distinguished from independent evidence that the airport itself was directly struck.

1.3 The Damaged Saudia Aircraft at Riyadh Airport

A further development concerned a commercial aircraft belonging to Saudi Arabia's national carrier, Saudia. Reuters reported on October 8 that the aircraft had caught fire while parked at a terminal at King Khalid International Airport and sustained serious damage. The information came from three people briefed on the incident, rather than a publicly released technical investigation or an official Saudi account (Azhari and Maccioni, 2026).

According to those sources, the aircraft may have been struck by fragments from a missile interception or by another projectile. Neither explanation had been conclusively established. Reuters separately verified video showing a substantial column of black smoke and flames rising from the airport. That verification established the location of the recorded fire but did not determine its precise cause.

The sources indicated that no passengers were believed to have been aboard the aircraft when the incident occurred. They could not, however, rule out injuries associated with the fire or impact. At the time of the Reuters report, Saudi Arabia's government media office, civil aviation authority, and Saudia had not publicly responded to the agency's requests for comment.

The reported aircraft damage indicates a physical incident more serious than the interruption of scheduled flights. Nevertheless, the circumstances do not conclusively establish that the Houthi ballistic missile directly struck the airport. Damage from interception fragments and damage from a direct missile impact involve different mechanisms, and determining which occurred would require reliable information about the projectile, its trajectory, and the resulting damage.

2. Flight Disruption and the Risk of Further Attacks

The October attacks caused substantial disruption to commercial aviation in Saudi Arabia, particularly at King Khalid International Airport. Airlines suspended services, passengers were evacuated during reported security incidents, and scheduled departures were interrupted. Missile launches and defensive interceptions also created uncertainty for aircraft operating in Saudi airspace, extending the consequences beyond the locations of reported impacts.

An airport can experience serious operational disruption even when an incoming missile is intercepted. Falling fragments may threaten aircraft, ground personnel, runways, and surrounding infrastructure. Air-defense operations also create risks associated with the identification and movement of civilian aircraft during periods of heightened military activity.

These conditions complicate decisions by aviation authorities and commercial carriers. A functioning airport may remain legally accessible while individual airlines suspend services or divert flights. Temporary interruptions, airline cancellations, and formal airspace closures are distinct measures, each reflecting different operational or regulatory considerations.

2.1 Airline Suspensions and Airspace Restrictions

Several international carriers announced temporary suspensions of Riyadh services following the October 8 missile incidents. Lufthansa Group stated that its airlines would suspend flights to the Saudi capital through October 16, citing developments in the Middle East. India's IndiGo canceled flights to and from Riyadh through October 9, while Air India and Akasa Air announced cancellations through October 10 (Lo Nostro and Srivastava, 2026).

The disruption also affected aircraft already operating scheduled services. Air India reported that a flight traveling from Delhi to Riyadh returned to the Indian capital, while Akasa Air canceled two services. Aviation analytics company Cirium reported that almost half of scheduled departures from Riyadh airport had been canceled by 15:00 GMT on October 8 (Azhari and Maccioni, 2026).

Airport operations experienced direct interruptions during the reported explosions. An Associated Press witness described passengers being instructed to evacuate the terminal and leave their checked luggage behind. Flightradar24 reported a period exceeding 80 minutes without a landing and 90 minutes without a takeoff at King Khalid International Airport. These observations documented a substantial interruption but did not establish a permanent closure of the facility (Ezzidin and Anna, 2026).

Concerns about the safety of Saudi airspace preceded the October incidents. On September 30, 2026, the European Union Aviation Safety Agency (EASA) issued Conflict Zone Information Bulletin CZIB-2026-09 concerning the Jeddah Flight Information Region. The bulletin identified risks associated with missile and drone operations, air-defense interceptions, falling debris, and the possible misidentification of civilian aircraft (EASA, 2026).

EASA recommended that affected operators avoid a specifically defined portion of Saudi airspace at all flight levels. It advised caution throughout the remainder of the Jeddah Flight Information Region, together with updated risk assessments, contingency planning, and close monitoring of official aeronautical information. The recommendations reflected the agency's assessment of regional aviation risks rather than a general closure of Saudi airspace.

The bulletin applies to operators governed by the relevant European aviation regulations and to qualifying third-country operators conducting services under EASA authorization. Its recommendations must be distinguished from binding airspace restrictions imposed by competent national authorities. Although aviation operators have regulatory responsibilities concerning risk assessment and operational safety, an EASA recommendation to avoid particular airspace is not itself equivalent to a sovereign prohibition on flight operations.

Commercial airlines may suspend services when their assessment of security risks exceeds acceptable operational limits, even where the destination remains legally accessible. Conversely, an airport's continued operation does not establish that every flight can proceed safely. Decisions concerning individual routes depend on evolving military activity, airspace conditions, and the precautions available to operators.

2.2 Is Another Attack on Riyadh Airport Expected?

The possibility of further attacks remains a credible security concern. Houthi representatives have repeatedly claimed missile and drone operations against Saudi aviation facilities and warned international airlines about operating in Saudi airspace. On October 8, the movement announced additional attacks involving ballistic and cruise missiles and threatened strikes against energy infrastructure (Ezzidin and Anna, 2026).

These statements establish the group's declared intention to continue military pressure against Saudi Arabia. The attacks reported during October also provide evidence of an ability to threaten targets beyond Yemen's borders. EASA had identified that capability in its September 30 assessment, referring to increased missile and drone activity affecting areas deeper inside Saudi territory, including Riyadh.

The continuing confrontation in Yemen provides the military context for those threats. Saudi-backed forces have undertaken operations to recover territory seized by the Houthis along Yemen's western coast, while the movement has directed attacks against Saudi airports and other infrastructure. Further hostilities could sustain the conditions associated with additional missile operations, although the connection between a particular battlefield development and an individual attack cannot always be established.

Neither the Houthis' public warnings nor the recent attack chronology identifies when or where another strike will occur. Aviation authorities and airlines consequently face an evolving security threat rather than a confirmed schedule of future attacks. Continued precautions are supported by the documented military activity, but another attack against King Khalid International Airport cannot be presented as inevitable.

3. The Yemen Conflict Behind the Airport Attacks

The October 2026 attacks occurred during a renewed escalation of Yemen's prolonged armed conflict. The Houthi movement, also known as Ansar Allah, seized the capital, Sanaa, in September 2014, following years of political instability and armed confrontation. On March 26, 2015, Saudi Arabia began leading a military intervention in support of Yemen's internationally recognized government, following a request from President Abd Rabbuh Mansour Hadi.

The intervention transformed the conflict into a prolonged regional confrontation involving ground operations, airstrikes, and cross-border attacks. Saudi-led forces conducted military operations against Houthi positions in Yemen, while the movement developed and employed missiles and drones against targets in Saudi territory. Iranian assistance to the Houthis contributed to the conflict's regional dimensions, although the extent of Iran's involvement in particular operations requires separate assessment.

A United Nations-mediated truce entered into force on April 2, 2022, and was renewed twice before formally expiring on October 2. The agreement provided for the suspension of offensive military operations inside Yemen and across its borders, greater access to Hudaydah's ports, and the resumption of certain commercial flights from Sanaa. The United Nations reported a significant reduction in violence and civilian casualties during the truce (United Nations Secretary-General, 2022).

The formal agreement expired without a further extension, but the subsequent period experienced substantially less large-scale fighting than earlier phases of the war. That relative calm deteriorated during 2026, when renewed hostilities brought Saudi-backed government forces and the Houthis into direct confrontation over strategically important territory in western Yemen.

The renewed fighting concentrated partly on Yemen's Red Sea coast and the approaches to the Bab el-Mandeb Strait. Reuters and the Associated Press reported that Houthi forces had seized coastal territory during September, including positions near the port of Mokha and the strait. Saudi-backed government forces subsequently announced counteroffensives and territorial gains in the same region. The precise extent of control over particular locations remained dependent on competing battlefield reports (Reuters, 2026; Associated Press, 2026).

The Bab el-Mandeb Strait connects the Red Sea with the Gulf of Aden and forms part of the maritime route linking Europe and Asia through the Suez Canal. Control of nearby coastal positions can affect shipping security, access to ports, and the ability of armed forces to threaten maritime traffic. The route became particularly significant amid continuing disruption to shipping through the Strait of Hormuz.

Saudi Arabia's renewed military operations were directed toward supporting Yemeni government forces seeking to reverse Houthi advances. The Houthis, meanwhile, described their attacks against Saudi infrastructure as responses to the kingdom's military involvement in Yemen. Their statements presented aviation and energy facilities as targets within a broader effort to exert military and economic pressure.

The declared reasons for these operations explain part of the confrontation's political and strategic context. They do not establish that any particular civilian facility made an effective contribution to military action or qualified as a lawful target. Those questions depend on the circumstances of individual attacks, including the military function of the objects selected.

The confrontation surrounding Riyadh's airport must be understood within this wider military campaign. Nevertheless, the continuation of armed hostilities does not automatically remove civilian protection from infrastructure belonging to an opposing state. The legal consequences depend on the classification and geographical scope of the relevant conflict, together with the rules governing the conduct of hostilities.

4. Armed Conflict Classification and Applicable Law

The classification of the hostilities involving the Houthis, Yemen's internationally recognized government, and Saudi Arabia determines which treaty rules of international humanitarian law apply. International and non-international armed conflicts are governed by overlapping but distinct legal regimes. Their classification depends on the parties involved and the factual character of the hostilities, rather than the terminology adopted by governments or armed groups.

The principal confrontation between Yemeni government forces and the Houthis has been classified as a non-international armed conflict. Saudi Arabia's intervention in support of the Yemeni government did not automatically alter that classification. Foreign military involvement can nevertheless create additional conflict relationships requiring separate legal assessment, particularly where armed operations involve different states or organized armed groups.

The October attacks also raise a geographical question. The principal conflict has been fought in Yemen, while the reported missile operations occurred within Saudi territory. Although customary international humanitarian law contains extensive rules governing the protection of civilians and civilian objects, the territorial application of those rules in some forms of extraterritorial non-international armed conflict remains contested.

The applicable legal framework consequently requires two related inquiries: the classification of the relevant hostilities and the geographical reach of the rules governing their conduct. The distinction is necessary before treating particular treaty provisions or customary rules as directly applicable to an individual operation.

4.1 Non-International and International Armed Conflicts

Common Article 2 of the Geneva Conventions establishes the principal treaty basis for international armed conflicts between states. By contrast, non-international armed conflicts involve sufficiently intense armed violence between governmental forces and organized armed groups, or between such groups. The organization of the parties and intensity of the violence are central criteria, as developed in the jurisprudence of the International Criminal Tribunal for the former Yugoslavia and subsequent international practice.

In its 2019 detailed findings on Yemen, the United Nations Group of Eminent International and Regional Experts concluded that the confrontation between Yemeni government forces and the Houthis qualified as a non-international armed conflict. The Group identified the organization of the Houthi movement and the sustained intensity of the fighting as sufficient to satisfy the applicable requirements (UN Human Rights Council, 2019, para. 46).

The Group also concluded that the intervention of the Saudi-led coalition in March 2015 did not change the conflict's non-international character. Coalition forces had entered the conflict at the request of Yemen's government and in support of its operations against an organized non-state armed group. On that basis, the Group considered coalition members parties to the preexisting non-international armed conflict (UN Human Rights Council, 2019, para. 50).

Governmental consent is significant in this context. As explained in the ICRC's 2024 opinion paper on armed conflict classification, foreign military operations conducted with the territorial state's valid consent do not ordinarily create an international armed conflict between those states. Operations undertaken without such consent may raise different classification issues, depending on the circumstances.

Multiple armed conflicts can also exist simultaneously within the same broader confrontation. Relations between governments, organized armed groups, and foreign military forces must be considered separately where the relevant legal criteria require it. The classification reached by the UN experts for the principal Yemen conflict does not conclusively determine the legal character of every military operation involving its participants in October 2026.

Houthi attacks across the Saudi-Yemeni border do not, by themselves, establish that the movement is acting as a state. A non-state armed group can engage in cross-border hostilities without acquiring statehood or transforming the conflict into an international armed conflict. A different question arises if its conduct is attributable to another state under the relevant international legal standards.

In Prosecutor v. Tadić, the ICTY Appeals Chamber considered the degree of control exercised by a foreign state over an organized armed group when determining whether an armed conflict had an international character. Its judgment of July 15, 1999, adopted an overall-control approach for that classification question (ICTY, 1999).

The International Court of Justice addressed a distinct question in Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v. Serbia and Montenegro). In its February 26, 2007 judgment, the Court rejected overall control as the general basis for attributing particular conduct to a state. It reaffirmed the relevance of effective control over the operation in question, while expressly declining to decide whether overall control was appropriate for classifying armed conflicts (ICJ, 2007, paras. 398–406).

The two judgments concern related but legally distinct inquiries. Classification addresses the character of an armed conflict, while attribution determines whether particular conduct engages a state's international responsibility. Effective control is not the only possible basis of attribution under international law, but general political alignment or military assistance does not automatically establish responsibility for every operation conducted by an armed group.

Allegations of Iranian support for the Houthis must be considered within these distinctions. Such support does not, without further evidence satisfying the applicable legal standards, establish that Iran directed the October airport attacks or that the relevant hostilities constituted an international armed conflict between Iran and Saudi Arabia.

A separate difficulty concerns the geographical application of humanitarian law to attacks within the territory of a state participating in a non-international armed conflict abroad. The ICRC's 2024 opinion paper distinguishes hostilities spreading into a neighboring state from an extraterritorial conflict in which a state fights an organized armed group within another state's territory.

For the latter situation, the ICRC recognizes that the law is not fully settled on whether international humanitarian law applies throughout the territory of the intervening state. It identifies substantial legal grounds supporting such application while also emphasizing the continuing relevance of international human rights law, whose rules will ordinarily provide the more specific framework in many circumstances within that state's territory (ICRC, 2024).

The October attacks against Riyadh cannot be assessed merely by assuming that every rule applicable to fighting in Yemen extends automatically throughout Saudi Arabia. The conflict's classification, the connection between the attacks and the hostilities, and the geographical scope of the relevant obligations all require consideration. This uncertainty does not establish an absence of legal protection for civilians or civilian aviation.

4.2 Treaty Obligations and Customary Humanitarian Law

The four Geneva Conventions of 1949 establish the principal treaty framework for protecting persons affected by armed conflict. Common Article 3 applies to non-international armed conflicts and requires humane treatment of persons who are not, or are no longer, actively participating in hostilities. It prohibits murder, cruel treatment, torture, hostage-taking, and certain other abuses against protected persons.

Common Article 3 binds every party to a qualifying non-international armed conflict, including organized armed groups. Its protection is fundamental, but it does not contain the detailed rules governing military objectives, proportionality, and precautions found in later treaty instruments. These questions require consideration of other applicable treaty provisions and customary international humanitarian law.

Additional Protocol II develops the law governing certain non-international armed conflicts, subject to more demanding conditions than Common Article 3. Article 1 requires a conflict involving a state's armed forces and organized opposing forces under responsible command, exercising sufficient territorial control to conduct sustained and concerted military operations and implement the Protocol.

Yemen ratified Additional Protocol II on April 17, 1990, while Saudi Arabia became a party on November 28, 2001. Their participation in the treaty is established, but individual provisions remain subject to the Protocol's material and territorial requirements (ICRC Treaty Database).

The UN Group of Eminent Experts concluded in 2019 that Additional Protocol II applied to the conflict between Yemeni government forces and the Houthis. It found that the movement's organization and territorial control satisfied the conditions established in Article 1 (UN Human Rights Council, 2019, para. 47). This finding concerns the conflict examined by the Group and does not independently resolve the geographical application of the Protocol to the October 2026 attacks inside Saudi Arabia.

Article 13 of Additional Protocol II requires protection of the civilian population against the dangers arising from military operations and prohibits making civilians the object of attack. The Protocol does not reproduce the detailed definition of military objectives or the specific provisions on proportionality and precautions contained in Additional Protocol I.

Additional Protocol I principally governs international armed conflicts. Saudi Arabia acceded to it on August 21, 1987, and Yemen ratified it on April 17, 1990. Its provisions include Article 48 on distinction, Article 51 on civilian protection, Article 52 on civilian objects and military objectives, and Article 57 on precautions in attack. Their direct application depends on the legal classification and circumstances of the relevant hostilities, not merely on the states' treaty participation.

Customary international humanitarian law contains additional rules governing the conduct of hostilities in both international and non-international armed conflicts. The ICRC's Customary International Humanitarian Law study identifies the distinction between civilian objects and military objectives in Rule 7 and the definition of military objectives in Rule 8. Rules 11–13 concern indiscriminate attacks, Rule 14 addresses proportionality, and Rules 15–21 concern precautions in attack (Henckaerts and Doswald-Beck, 2005).

The ICRC study is an authoritative analysis of customary humanitarian law rather than a treaty or an independent source of legislative authority. Customary rules derive their legal force from general state practice accepted as law, commonly described as opinio juris. The study's findings are particularly relevant where treaty provisions do not expressly regulate particular aspects of non-international armed conflicts.

Within the applicable scope of international humanitarian law, these customary obligations bind organized armed groups as well as governmental forces. Civilians and civilian objects are protected against direct attack, and military objectives must be identified according to the relevant legal criteria. Attacks against legitimate military objectives remain subject to restrictions concerning indiscriminate effects, excessive incidental civilian harm, and feasible precautions.

The position is more complicated where the geographical application of the relevant armed conflict rules remains disputed. The ICRC's 2024 analysis recognizes that the extension of international humanitarian law to the territory of a state fighting an organized armed group abroad is not conclusively settled in every circumstance. Its interpretation provides substantial grounds for applying humanitarian law to connected hostilities, while acknowledging the continuing importance of international human rights law.

For the Riyadh operations, the customary rules governing distinction, proportionality, and precautions provide the central standards for assessing military targeting, insofar as the attacks fall within the applicable scope of the armed conflict. Their relevance must be distinguished from a categorical assumption that every provision of Additional Protocol I or II directly governs the strikes.

The legal assessment must consequently address both the status of the objects attacked and the circumstances in which the applicable obligations operated. Neither the existence of hostilities in Yemen nor the Houthis' declared military objectives independently establishes that an attack against civilian airport infrastructure was lawful.

5. Can Civilian Airports Be Lawful Military Targets?

Civilian airports are protected against direct attack under international humanitarian law unless they qualify as military objectives. Their commercial importance, ownership by a state engaged in armed conflict, or contribution to the national economy does not independently remove that protection. An airport may serve military purposes, but its legal status depends on identifiable military functions and the circumstances of the proposed attack.

Article 52(2) of Additional Protocol I establishes two cumulative requirements for classifying an object as a military objective. It must make an effective contribution to military action through its nature, location, purpose, or use, and its destruction, capture, or neutralization must offer a definite military advantage in the circumstances prevailing at the time. The definition is also reflected in customary international humanitarian law (Henckaerts and Doswald-Beck, 2005, Rule 8).

The distinction is particularly significant for airports because civilian and military activities may operate within the same infrastructure. Military use can alter the status of an identifiable facility, or potentially a larger integrated installation, when both elements of the military-objective test are satisfied. It does not automatically eliminate protection from surrounding civilian facilities or relieve attackers of their obligations concerning proportionality and precautions.

5.1 Effective Military Contribution and Definite Advantage

The first requirement concerns an object's relationship with military action. Article 52(2) recognizes four grounds for that relationship: nature, location, purpose, and use. Nature refers to an object's inherent military character, while location concerns its military significance in a particular geographical setting. Purpose addresses intended future employment, whereas use concerns its existing function.

An airport runway supporting military aircraft may contribute effectively to military operations. Facilities used to transport weapons, support military logistics, or coordinate operational communications may also qualify, depending on their actual functions. Such classifications require a sufficiently established connection with military action rather than an assumption that civilian infrastructure could theoretically become useful to armed forces.

Future military use may be relevant when assessing an object's purpose, but it cannot rest solely on speculation. The assessment must reflect the information reasonably available to those planning or deciding upon the attack. Absolute certainty is not required in every circumstance, although attackers remain responsible for taking feasible measures to verify that the intended target qualifies as a military objective.

The second requirement concerns the definite military advantage anticipated from neutralizing the object. Interrupting military aircraft operations or preventing an identifiable military deployment may satisfy that requirement. Disrupting tourism, reducing commercial airline revenue, or damaging Saudi Arabia's international reputation would not independently establish the necessary military advantage.

The ICRC's 2026 guidance on the escalating conflict in the Middle East emphasizes that civilian infrastructure cannot be targeted merely because its destruction would weaken an adversary's economy or general war effort. The relevant contribution must concern military action, and the anticipated advantage must be definite rather than speculative (ICRC, 2026).

Military-objective status can also change. A facility previously used for military operations does not necessarily retain that status indefinitely, while infrastructure ordinarily devoted to civilian activities may acquire a qualifying military function. The assessment depends on the circumstances prevailing at the time of the proposed attack, including sufficiently established intended military use.

5.2 Military Facilities Within Civilian Airports

Airports present particular legal difficulties when commercial aviation and military operations share infrastructure. An installation may accommodate civilian passengers while supporting military logistics or aircraft movements. Such dual-use arrangements do not automatically prevent military targeting, but the relevant object must independently satisfy the established definition of a military objective.

A hangar housing combat aircraft, a communications installation supporting military operations, or a runway used for military deployments may qualify. The assessment concerns the object's effective contribution to military action and the definite advantage anticipated from its neutralization. Occasional military presence, without further evidence of the facility's function, does not automatically establish that the entire airport may be attacked.

The distinction between an individual facility and a larger installation is not absolute. Depending on the operational relationship between its components, a broader integrated airport installation may itself satisfy the military-objective test. Nevertheless, military use of one building cannot justify treating unrelated passenger terminals, administrative facilities, or commercial aircraft as lawful targets without examining their status.

Civilian functions remain legally significant even where an airport installation qualifies as a military objective. Attacking a shared runway, for example, could endanger civilian aircraft and personnel or cause reasonably foreseeable harm arising from the interruption of essential civilian services. Such consequences must be assessed under the rules governing incidental civilian harm, proportionality, and feasible precautions.

The presence of civilians does not necessarily make an otherwise lawful military objective immune from attack. Their protection instead places restrictions on how an operation may be conducted. The expected consequences for passengers, employees, and nearby civilian facilities must remain part of the attacker's assessment.

5.3 The Military Status of King Khalid Airport

King Khalid International Airport serves Riyadh through extensive commercial passenger and aviation operations. Its ordinary functions are civilian, and its importance to Saudi Arabia's transportation network does not itself establish military-objective status. The legal question is whether a particular facility, or an identifiable integrated installation, made an effective contribution to military action when the reported attacks occurred.

The Reuters and Associated Press reporting of October 8, 2026, describes Houthi claims against the airport, Saudi missile interceptions, aviation disruption, and reported physical damage. Those accounts do not substantiate a particular military use of King Khalid International Airport that would satisfy Article 52(2). Nor do the publicly reported Houthi statements identify a specific military installation whose neutralization offered a definite military advantage.

Saudi Arabia's possession of military air bases elsewhere does not establish the status of King Khalid International Airport. Information concerning another airfield cannot substitute for evidence about the intended target in Riyadh. The relevant assessment requires information about the facility selected, its military function, and the advantage reasonably anticipated from attacking it.

The available reporting does not demonstrate that the Houthis selected a qualifying military objective at King Khalid International Airport. That finding is limited to the evidence publicly substantiated concerning the incidents; it does not establish that military activity anywhere within the airport was impossible. Without reliable evidence of a qualifying military function, the airport's civilian character remains the relevant starting point for the legal assessment.

6. Ballistic Missiles and the Protection of Civilians

Ballistic missiles are not prohibited as a general category of weapons under international humanitarian law. Their use must nevertheless comply with the rules governing the conduct of hostilities, and particular payloads or weapon components may be subject to additional restrictions. The legality of an attack depends on the weapon's characteristics, the intended target, its expected effects, and the circumstances of employment.

Missile attacks against functioning airports create particular risks because civilian aircraft, passenger terminals, employees, and fuel installations may be located close to the intended impact point. The foreseeable consequences can extend beyond the immediate target, especially where explosive weapons are employed near concentrated civilian activity.

International humanitarian law separately prohibits attacks directed against civilians or civilian objects, indiscriminate attacks, and attacks expected to cause excessive incidental civilian harm. A missile directed toward a legitimate military objective may still be used unlawfully if it cannot be directed sufficiently accurately or if the attack violates proportionality or precautionary obligations (Henckaerts and Doswald-Beck, 2005, Rules 11–15).

6.1 Indiscriminate Attacks and Missile Accuracy

An attack is indiscriminate when it is not directed at a specific military objective, employs means or methods that cannot be so directed, or produces effects that cannot be limited as international humanitarian law requires. The prohibition concerns the manner in which force is used, including the characteristics of weapons that are not independently prohibited by treaty.

Missile accuracy must be assessed in relation to the intended target. Relevant factors include guidance technology, reliability, expected dispersion, explosive effects, and the proximity of civilian facilities. A weapon capable of striking a large military installation may present different legal difficulties when directed toward a smaller object surrounded by densely occupied infrastructure.

The International Criminal Tribunal for the former Yugoslavia addressed these questions in Prosecutor v. Milan Martić. The case concerned rocket attacks against Zagreb on May 2 and 3, 1995, using M-87 Orkan rockets. The Trial Chamber examined the weapon's characteristics, dispersion pattern, and firing distance before finding that its employment against the city was indiscriminate (ICTY, 2007, paras. 462–463).

The Appeals Chamber upheld the relevant finding on October 8, 2008. It rejected the argument that the possible presence of military objectives in Zagreb justified the use of rockets that could not strike specific targets with sufficient accuracy under the circumstances. The judgment emphasized the weapon's dispersion and the conditions in which it was employed (ICTY, 2008, paras. 247–252).

The Martić judgment does not establish that every ballistic missile is inherently indiscriminate. Its conclusion concerned the M-87 Orkan and the circumstances of the Zagreb attacks. Applying the same reasoning to Riyadh requires evidence about the particular missiles used and their capacity to distinguish the intended military objectives from surrounding civilian infrastructure.

The public reporting concerning the October 2026 incidents does not establish the precise model, guidance capabilities, intended impact point, or expected accuracy of every missile launched. Those gaps prevent a definitive technical assessment comparable to the one undertaken in Martić. The reported use of ballistic missiles alone is insufficient to determine whether the attacks were indiscriminate.

6.2 Proportionality and Precautions at an Operating Airport

An attack against a military objective must still comply with proportionality. Customary international humanitarian law prohibits attacks expected to cause incidental civilian deaths, injuries, or damage to civilian objects excessive in relation to the concrete and direct military advantage anticipated. The military status of a target does not remove this independent restriction (Henckaerts and Doswald-Beck, 2005, Rule 14).

At a functioning international airport, foreseeable harm may include casualties among passengers and aviation personnel, damage to civilian aircraft, and destructive effects on nearby buildings. The interruption of civilian services may also have indirect consequences. Such effects are legally relevant when they have a sufficient causal relationship with the attack and are reasonably foreseeable at the time.

The ICRC recognizes that foreseeable indirect or reverberating civilian harm must be considered in proportionality assessments, including harm resulting from the loss of essential services. The treatment of particular indirect effects may raise questions about causation and foreseeability. Commercial inconvenience, reduced airline revenue, or canceled flights do not automatically amount to the civilian harm assessed under the proportionality rule (ICRC, 2024).

Proportionality is assessed prospectively, using information reasonably available to those planning or deciding upon an attack. Civilian casualties and material damage may provide evidence relevant to a subsequent investigation, but they do not independently establish what the attacker could reasonably have anticipated. The assessment also requires identification of the concrete and direct military advantage expected from the operation.

Precautionary obligations impose further requirements. Article 57 of Additional Protocol I expresses duties concerning target verification, weapon selection, attack timing, and measures to avoid or minimize incidental civilian harm. Corresponding customary rules require feasible precautions in both international and non-international armed conflicts where the relevant humanitarian law governs the operation (Henckaerts and Doswald-Beck, 2005, Rules 15–21).

Those planning an airport attack must consider available information about civilian flights, aircraft locations, passenger activity, and surrounding facilities. Effective advance warning is required when an attack may affect civilians unless circumstances do not permit. An attack must also be canceled or suspended when it becomes apparent that the intended target is not a military objective or that the operation would violate proportionality.

The October incidents raise substantial questions under these rules. Saudi authorities reported civilian deaths and injuries, while Reuters described serious damage to a parked commercial aircraft on October 8. The available accounts do not establish the military intelligence, anticipated advantage, expected civilian harm, or feasible precautions considered by those responsible for each operation. Those evidentiary limitations prevent a definitive assessment of proportionality or precautionary compliance.

7. Houthi Threats Against Airlines and Saudi Airspace

The Houthis' warnings to international airlines raise legal questions distinct from the missile attacks themselves. Following the October 2026 operations, Houthi representatives warned commercial carriers against operating in Saudi airspace, which the movement described as an area of military operations. The warnings accompanied claims of attacks against Saudi airports and threats directed at additional infrastructure (Associated Press, 2026).

Article 1 of the 1944 Convention on International Civil Aviation, commonly known as the Chicago Convention, recognizes the complete and exclusive sovereignty of states over the airspace above their territory. Saudi Arabia consequently possesses the sovereign authority to regulate civilian aviation within its territorial airspace, subject to its international obligations. A non-state armed group does not acquire comparable authority by announcing military operations.

Article 89 of the Chicago Convention addresses war and emergency conditions. It provides that the Convention does not affect the freedom of action of contracting states affected by war, whether as belligerents or neutrals. This provision does not confer sovereign powers on armed groups or displace other applicable international obligations, including the rules governing hostilities.

The Chicago Convention also contains protections concerning civilian aircraft. Article 3 bis recognizes the obligation of states to refrain from using weapons against civil aircraft in flight, subject to its terms and the relationship with the United Nations Charter. Its operation in wartime must be considered alongside Article 89 and the applicable rules of international humanitarian law.

Article 3 bis does not directly regulate the conduct of the Houthis as a non-state armed group. Nor does its specific protection concerning aircraft in flight independently determine the legality of attacks against parked aircraft or airport terminals. Those questions require consideration of the applicable legal regime and the civilian or military status of the objects concerned.

The Houthis' declarations consequently cannot establish a legally binding closure of Saudi airspace. Their warnings may nevertheless influence aviation safety assessments and airline decisions. A carrier may suspend flights in response to credible military threats without recognizing the armed group's authority to regulate air traffic.

International humanitarian law addresses warnings from a different perspective. Where that law governs an operation, parties must take feasible precautions to protect civilians, including giving effective advance warning of attacks that may affect the civilian population unless circumstances do not permit. Article 57(2)(c) of Additional Protocol I expresses this requirement, which is also reflected in customary Rule 20 (Henckaerts and Doswald-Beck, 2005).

A warning cannot independently transform civilian aircraft or airport facilities into military objectives. Nor does it relieve an attacker of obligations concerning distinction, proportionality, and precautions. Civilians who remain in an area after receiving a warning do not lose their protection merely because they have not departed.

The prohibition on terrorizing civilians introduces another distinction. Article 51(2) of Additional Protocol I and Article 13(2) of Additional Protocol II prohibit acts or threats of violence whose primary purpose is to spread terror among the civilian population. The ICRC identifies a corresponding customary prohibition applicable in both international and non-international armed conflicts (Henckaerts and Doswald-Beck, 2005, Rule 2).

The primary purpose of a threat is decisive. A warning intended to reduce civilian exposure to an impending military operation is not automatically prohibited, even if it causes alarm. A threat primarily designed to frighten civilians may fall within the prohibition, depending on its content, circumstances, and connection with the hostilities.

The geographical application of humanitarian law to the Riyadh operations also requires the qualification established by the conflict-classification analysis. The ICRC's 2024 opinion paper recognizes that the territorial reach of certain extraterritorial non-international armed conflicts remains unsettled. The customary prohibition on terrorizing civilians is established, but its application to a particular cross-border operation requires consideration of the relevant conflict and applicable legal framework (ICRC, 2024).

The Houthis' warnings do not establish lawful authority over Saudi airspace or eliminate the protection of civilian aviation. Their characterization as prohibited threats would require evidence concerning their primary purpose. The existence of military hostilities and the warnings' intimidating consequences are relevant circumstances, but neither independently resolves that question.

8. Aviation Security Treaties and War Crimes

Attacks against international airports may engage several bodies of international law. International humanitarian law regulates the conduct of hostilities where its conditions of application are satisfied. International aviation security conventions establish criminal offenses and duties concerning jurisdiction, prosecution, extradition, and cooperation between states.

These regimes operate through different legal mechanisms. Conduct excluded from an aviation security convention because it constitutes an activity of armed forces governed by international humanitarian law may remain unlawful under that law. Conversely, conduct falling within a civil aviation offense does not automatically satisfy the elements of a war crime.

Individual criminal responsibility requires a further inquiry. An unlawful attack does not necessarily constitute an offense within the jurisdiction of the International Criminal Court. The relevant crime, its mental element, the character of the armed conflict, and the jurisdiction of the competent tribunal must be established separately.

8.1 The Montreal and Beijing Aviation Conventions

The international treaty framework protecting civil aviation developed partly in response to hijackings, attacks against aircraft, and violence at airports. The 1971 Convention for the Suppression of Unlawful Acts against the Safety of Civil Aviation, adopted in Montreal, established offenses involving violence aboard aircraft, damage to aircraft in service, and interference with air navigation facilities under specified conditions.

The supplementary protocol adopted on February 24, 1988, extended the framework to certain acts of violence at airports serving international civil aviation. It addressed serious violence against persons and attacks affecting airport facilities or aircraft not in service, where the conduct endangered or was likely to endanger airport safety.

The 2010 Convention on the Suppression of Unlawful Acts Relating to International Civil Aviation, adopted in Beijing, consolidated and expanded the earlier framework. Article 1(2) establishes offenses involving intentional and unlawful use of a device, substance, or weapon to commit serious violence at an airport serving international civil aviation or to damage facilities, certain aircraft, or airport services under the prescribed conditions (ICAO, 2010).

The airport offenses are subject to specific legal elements. Article 1(2)(a) concerns violence against a person at an international airport that causes or is likely to cause serious injury or death. Article 1(2)(b) covers destruction or serious damage to airport facilities or aircraft not in service, or disruption of airport services, where the conduct endangers or is likely to endanger safety at the airport.

Article 1(3) also addresses specified threats, including conduct causing another person to receive such a threat under circumstances indicating its credibility. The precise elements differ between the provisions. The existence of a threatening statement does not automatically establish an offense under the Convention.

Saudi Arabia deposited its instrument of accession to the Beijing Convention on April 24, 2026. Under the Convention's entry-into-force provisions, it entered into force for the Kingdom on June 1, 2026. Saudi Arabia was consequently a party when the October airport incidents occurred (ICAO, 2026).

The reported damage to the Saudia aircraft raises a distinct question concerning aircraft status. Article 1(1)(b) addresses destruction or qualifying damage to an aircraft in service, while Article 1(2)(b) concerns aircraft not in service at an international airport. The applicable classification cannot be inferred merely from an aircraft being parked.

Article 2 defines the period during which an aircraft is considered in service. That period begins with preflight preparation by ground personnel or crew for a particular flight and continues until 24 hours after landing. A parked aircraft may consequently remain in service for treaty purposes. The information publicly reported about the Saudia aircraft does not establish the operational details necessary to determine its classification under these provisions.

The Beijing Convention also contains an exclusion relating to armed conflict. Article 6(2) provides that activities of armed forces during an armed conflict, as understood and governed by international humanitarian law, are not governed by the Convention. It separately addresses official activities of state military forces governed by other rules of international law.

This exclusion may be relevant to military operations conducted by organized non-state armed groups. Its application depends on whether the particular conduct constitutes an activity of armed forces during an armed conflict governed by international humanitarian law. Membership in the Houthi movement does not automatically establish that every act committed by its members falls within Article 6(2).

The question is particularly significant given the legal uncertainty concerning the geographical reach of humanitarian law in some extraterritorial non-international armed conflicts. A determination that particular Houthi operations fall within the armed-conflict exclusion would require examination of their connection with the hostilities and the applicable legal rules.

Article 6(3) preserves an important limitation on the exclusion. It specifies that the preceding provision does not make otherwise unlawful conduct lawful or prevent prosecution under other applicable laws. An operation excluded from the Beijing Convention may consequently remain prohibited under international humanitarian law or criminalized under another applicable legal regime.

Article 24 further establishes that the Beijing Convention prevails over the 1971 Montreal Convention and the 1988 supplementary protocol as between states parties to the Beijing Convention. This treaty-specific priority does not universally extinguish the earlier instruments, which may remain relevant where participation or other applicable conditions differ.

The October attacks cannot automatically be classified as Beijing Convention offenses because international airports were affected. The relevant conduct would have to satisfy a defined offense, the Convention's scope and jurisdictional requirements, and any applicable exclusion. The reported civilian casualties and aircraft damage warrant examination under these provisions but do not independently establish criminal liability.

8.2 War Crimes and Individual Criminal Responsibility

Serious violations of international humanitarian law may give rise to individual criminal responsibility. Intentionally directing attacks against civilians can constitute a war crime when the applicable legal and mental elements are established. The precise offenses differ according to the classification of the armed conflict and the legal instrument governing the relevant court.

Article 8 of the Rome Statute distinguishes crimes committed during international armed conflicts from those committed during non-international armed conflicts. Article 8(2)(b)(i) criminalizes intentionally directing attacks against civilians in international armed conflicts. Article 8(2)(b)(ii) separately addresses intentionally directing attacks against civilian objects that are not military objectives.

For non-international armed conflicts, Article 8(2)(e)(i) criminalizes intentionally directing attacks against the civilian population or individual civilians not taking direct part in hostilities. The corresponding provisions do not contain an identical general offense concerning attacks against civilian objects. Other provisions protect particular buildings, facilities, and categories of objects under specified conditions.

This difference does not authorize attacks against civilian objects during non-international armed conflicts. Such attacks remain prohibited under customary international humanitarian law. The distinction concerns the particular offenses enumerated within the Rome Statute rather than the existence of the underlying humanitarian prohibition.

Disproportionate attacks require similar precision. Article 8(2)(b)(iv) criminalizes certain attacks launched with knowledge that the expected incidental civilian harm would be clearly excessive in relation to the concrete and direct overall military advantage anticipated. The provision concerns international armed conflicts and establishes specific criminal-law requirements.

Article 8(2)(e) does not establish an identical general offense concerning disproportionate attacks in non-international armed conflicts. A violation of the customary proportionality rule must consequently be distinguished from proof of a particular offense within the Court's statutory jurisdiction.

Individual criminal responsibility also requires evidence concerning the accused person's conduct and mental state. The selection of targets, orders issued, knowledge of civilian circumstances, and participation in the relevant operation may be significant. Article 25 of the Rome Statute establishes different modes of individual responsibility, while Article 28 addresses responsibility of commanders and other superiors under specified conditions.

The reported deaths at Saudi airports do not independently establish the required criminal elements. An investigation would need to determine whether civilians were deliberately targeted, whether a qualifying military objective existed, and what relevant information was available to those responsible for the attack. The requirements for liability must be established for the particular offense alleged.

The International Criminal Court's jurisdiction presents additional obstacles. Saudi Arabia and Yemen are not states parties to the Rome Statute. The Court does not automatically acquire territorial jurisdiction over an alleged offense merely because it occurred in Saudi Arabia.

Under Article 12(2), jurisdiction may arise where the relevant conduct occurs on the territory of a state party or a state accepting the Court's jurisdiction, or where the accused is a national of such a state. The nationality of victims does not independently establish jurisdiction under that provision.

Article 12(3) permits a non-party state to accept the Court's jurisdiction through a declaration. Article 13(b) also allows the United Nations Security Council, acting under Chapter VII of the UN Charter, to refer a situation to the Court. These possibilities cannot be presumed to apply to the Riyadh incidents.

Domestic criminal jurisdiction and other legally available accountability mechanisms must be considered separately. The absence of ICC jurisdiction over particular conduct does not, by itself, eliminate possible individual responsibility under applicable international or national law. Any prosecution would depend on the competent court's jurisdiction and sufficient evidence of the alleged offense.

9. Assessing the Legality of the Riyadh Attacks

The reported October 2026 attacks raise serious legal questions because the identified targets were international airports performing civilian functions. Saudi authorities attributed three deaths and 36 injuries to the October 6–7 incidents at Abha and Riyadh. The Houthis subsequently claimed another missile strike against King Khalid International Airport, while Reuters reported serious damage to a parked Saudia aircraft on October 8.

The evidence publicly reported concerning the Riyadh operations does not substantiate a particular military objective selected by the Houthis. Their statements identified King Khalid International Airport as a target without establishing an effective contribution to military action or a definite advantage from neutralizing an identifiable facility. Under the military-objective test, the airport's economic and political significance is insufficient to justify a direct attack.

That assessment must be distinguished from a definitive finding about every possible military activity within the airport. The reporting does not establish the facility's complete operational circumstances or the intelligence available to those responsible for the attacks. It provides no substantiated military-objective justification, but does not exclude every hypothetical possibility of qualifying military use.

The legal consequences depend partly on whether international humanitarian law governs the particular cross-border operation. Section 4 identified the uncertainty concerning its geographical application in some extraterritorial non-international armed conflicts. The following assessment concerns the targeting rules applicable where the necessary connection with an armed conflict and the geographical conditions for their operation are established.

An attack intentionally directed against civilian airport infrastructure lacking military-objective status would violate the prohibition on attacking civilian objects. Evidence that the attacker deliberately selected the airport because of its civilian transportation functions could be relevant to that determination. The publicly reported Houthi statements identify the airport as a target but do not establish the full circumstances of target selection.

If a genuine military objective existed within the airport, the attack would remain subject to the prohibitions on indiscriminate and disproportionate attacks. The existence of military use would not excuse an inability to direct the chosen weapon at the intended objective or an expectation of excessive incidental civilian harm. The weapon's characteristics and the precautions adopted would require separate assessment.

The reported missile operations and their consequences raise concerns under these rules. Nevertheless, the available accounts do not establish the precise weapon specifications, intended impact points, anticipated military advantage, or foreseeable civilian harm associated with each strike. Without such information, neither compliance nor violation of every applicable targeting obligation can be conclusively determined.

A lawful attack against a military objective is also a legally possible characterization where the relevant conditions are satisfied. Yet the publicly reported evidence concerning King Khalid International Airport does not substantiate those conditions. The possibility of a lawful military operation cannot substitute for factual support establishing the status of the selected target and compliance with the applicable restrictions.

The October 8 aircraft incident creates an additional evidentiary difficulty. Reuters reported serious damage to a parked Saudia aircraft, while the cause remained uncertain. Its independently verified footage established smoke and flames at the airport, but did not conclusively identify the projectile responsible for the reported damage.

Damage from missile interception debris must be distinguished from a direct missile impact. The distinction concerns the physical sequence of events and the legal assessment of the conduct involved. Defensive interception does not automatically absolve an attacker of responsibility for reasonably foreseeable consequences of the original operation, but neither does it establish the precise causal or legal responsibility for every resulting injury or damaged object.

The proportionality assessment would depend on the foreseeable effects of the attack and the anticipated military advantage. An investigation would also need to determine whether feasible precautions were taken to verify the target, select appropriate means and methods, and avoid or minimize civilian harm. The reported consequences provide important evidence, but cannot replace an examination of the decisions preceding the attack.

Saudi Arabia's possible military response presents a different legal question. Article 51 of the United Nations Charter recognizes the inherent right of individual or collective self-defense if an armed attack occurs. Whether particular military action is justified on that basis depends on the armed-attack threshold and the requirements of necessity and proportionality under the law governing the use of force.

Operations against non-state armed groups across international borders also raise questions concerning the legal basis for using force within another state's territory. Those questions cannot be resolved solely by identifying the group responsible for an attack. The legality of resorting to force must be distinguished from the separate humanitarian rules governing how military operations are conducted.

Even where self-defense is available, military responses remain subject to applicable international humanitarian law. The proportionality requirement governing the necessity and scale of force used in self-defense differs from humanitarian law's rule concerning excessive incidental civilian harm. Neither permits deliberately directing attacks against protected civilians or civilian objects.

The evidence presently reported supports a limited legal conclusion. The October incidents caused civilian casualties, disrupted international aviation, and were accompanied by Houthi claims directed against airport infrastructure. The reporting does not substantiate a qualifying military objective at King Khalid International Airport or establish all the circumstances necessary for a definitive determination of the lawfulness of each operation.

A complete assessment would require evidence concerning the selected targets, their military functions, the weapons used, and the information reasonably available to those directing the attacks. The absence of that evidence limits any final determination of individual criminal responsibility. It does not diminish the legal significance of attacks publicly claimed against functioning civilian airports.

Also read

• Houthi Attacks on Saudi Arabia: Self-Defense, Energy Sites and the Law of Armed Conflict

• How 9/11 Changed Airport Security and International Aviation Law

• The Legality of a Houthi Bab el-Mandeb Blockade under International Law

• US Strikes Iranian Oil Tankers: Military Objectives and Economic Warfare Under IHL

Conclusion

The Houthis cannot lawfully target King Khalid International Airport merely because it belongs to Saudi Arabia, contributes to the national economy, or serves a government participating in the Yemen conflict. Where international humanitarian law applies, particular airport facilities may become military objectives only when they satisfy the established legal requirements. Military use does not automatically remove protection from an entire airport or exempt an attack from the rules governing indiscriminate effects, proportionality, and precautions.

The October incidents warrant serious legal scrutiny. Saudi authorities reported three civilian deaths and 36 injuries across Riyadh and Abha airports, while subsequent reporting described extensive aviation disruption and serious damage to a parked Saudia aircraft. The publicly available evidence does not substantiate a qualifying military objective at King Khalid International Airport or conclusively establish that the Houthis' October 8 ballistic missile directly struck its claimed target. Those limits prevent a definitive determination concerning every reported operation.

The continuing threat to commercial aviation is nevertheless established by the reported missile activity and repeated Houthi warnings. Further attacks remain possible, although their timing and location cannot be reliably predicted. International law does not permit civilian protection to be displaced by declarations of military necessity unsupported by the relevant facts, nor can an armed group acquire sovereign authority over another state's airspace through unilateral threats. Civilian aviation remains protected by the applicable international legal rules even amid an escalating armed conflict.

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