When Sanctions Affect IHL: Third States’ Obligations to Ensure Respect for the Geneva Conventions in the Context of U.S. Sanctions against Iranian Airlines

[Dr. Pouria Askary is an Associate Professor of International Law at Allameh Tabataba’i University.

Dr. Katayoun Hosseinnejad is an independent researcher and consultant.]

On August 24, 2026, the U.S. Department of the Treasury launched a new economic campaign against Iran, which it described as targeting the country’s “lifelines”. The so called “Operation Economic Outcast” as reflected in the statement of the Secretary of the Treasury Scott Bessent, encompasses a message to all countries: “[t]hose who stand with the United States will reap the rewards of our partnership. Those who tether themselves to Tehran should expect to share in the isolation of a withering regime”. The statement on the website of the Department of Treasury further indicates that: “[e]very country will be given a defined timeline to shut down the Iran-related activity we have identified. If they fail to act, Treasury will act”. 

This new campaign encompasses a broad range of secondary sanctions, including measures targeting matters related to all Iranian civil aviation airlines. As reflected in the press release issued on 8 September 2026, pursuant to Executive Order 13902, the U.S. Department of the Treasury’s Office of Foreign Assets Control (OFAC) designated 27 Iranian airlines. On the basis of this new sanction regime: 

“OFAC is suspending three Iran-related aviation authorizations to put additional pressure on the Iranian regime. These include authorizations that allowed for overflights, and for non-U.S. airlines to fly U.S.-origin or U.S.-controlled commercial aircraft into Iran.” 

The scope of these sanctions can best be understood in light of the current state of Iran’s civil aviation sector. With a population of more than 90 million and a territory that makes it the seventeenth-largest country in the world, decades of sanctions against its civil aviation sector, compounded by the devastating consequences of two recent aggressions, have reduced the country’s air transportation capacity to an unprecedented level. As a result, the active fleet of a country that was home to the oldest airline in West Asia and the second-oldest in Asia, and was among the 52 States that participated in the 1944 Chicago Conference, now stands at only 75 aircrafts. These aircrafts are operated by 23 airlines under the Civil Aviation Authority of the Islamic Republic of Iran, all of which are among the Iranian airlines sanctioned by the U.S., meaning that the entire Iranian civil aviation system is subject to sanctions. 

Further details on the scope and reach of these measures emerged in an interview with CNBC, in which Secretary Bessent announced that all Iranian airlines would be shut down by September 23 through the threat of secondary sanctions. In the same interview, he further clarified: “[i]f they land, you cannot provide them with fuel, you cannot provide them with landing services, you cannot sell them tickets, or you will be knocked out of the dollar system”.

The services mentioned by Secretary Bessent fall within what is generally understood as “ground handling,” which is an integral part of airline operations and include activities carried out at an aerodrome to prepare a civil aircraft and its passengers for a flight. According to the International Air Transport Association (IATA), ground handling encompasses a broad range of operations including passenger and baggage handling, aircraft servicing and safety procedures, fueling operations, and airside safety oversight. The essential nature of these services is further reflected in the increasing regulatory attention given to ground handling, as evidenced, for example, by the EU ground handling regulations, which require competent authorities to exercise oversight over ground handling organizations.

The provision of such services is governed by applicable national legislations, regional regulations, as is the case in the EU, bilateral air service agreements, and contractual arrangements between airlines and service providers. Importantly, however, the entities responsible for providing these services are not necessarily private commercial actors. As discussed in detail by A. Santos, airports and ground-handling services may be operated by private companies, public-private entities, or directly by State organs and entities exercising governmental authority. Consequently, sanctions that prohibit or deter the provision of aviation services to Iranian airlines can, in practice, extend beyond non-U.S. private actors and directly affect entities forming part of the governmental apparatus of third States. This is why Secretary Bessent stated on X that: “[a]t my direction, teams were dispatched across the globe to engage with countries and demand action against the Iranian regime”. This would mean that, where an airport, ground-handling service, or other essential aviation provider is operated by a State organ, an entity exercising public authority, or a private company operating under the jurisdiction of a State, a prohibition on providing services to a targeted Iranian airline could effectively constrain the State’s ability to exercise its governmental functions independently.

As is evident from the statements of the U.S. Secretary of the Treasury referred to above, the U.S. administration is placing other States in a position where they must either comply with OFAC directives or face potentially severe consequences, including exclusion from the U.S. dollar-based financial system. In other words, by leveraging its economic and financial power to implement the secondary sanctions, the United States seeks to influence the conduct of other States in ways that may seriously affect their sovereignty and independence. In brief, this is the essence of why secondary sanctions have been widely regarded as unlawful and illegitimate by academics, national authorities, the UN mandate holders, the UN Human Rights Council, as well as, the UNGA.

While most of the positions referred to above address the imposition of sanctions in general terms, the current situation between Iran and the U.S. requires consideration of an additional dimension: that an international armed conflict (IAC) is ongoing between the two States. Accordingly, alongside the general norms of international law, including the principle of non-intervention and applicable human rights obligations, the rules of IHL governing IACs are also applicable in assessing the legality of these coercive measures. 

The recent campaign targeting Iranian civil aviation, together with the naval blockade of Iran’s southern ports, have without any doubt far-reaching consequences for the life and wellbeing of Iranians. These measures further isolate the Iranian population and place significant numbers of jobs and the livelihoods of aviation-related workers and their families at risk. Moreover, Iranian imports of pharmaceuticals, medical products and many other essentials will heavily be affected by the new sanctions.

Although this post was written only a few days after the implementation of the new sanctions against Iranian airlines, their adverse effects on the lives and well-being of ordinary people are already becoming apparent, with reports that designated airlines have been banned from operating in some countries in the region and beyond. Videos and reports shared on social media have shown ordinary Iranians stranded at airports, uncertain about what will happen next. Many flights have already been cancelled, while it remains unclear whether, and to what extent, they can resume. Beyond these immediate disruptions, the broader human consequences of such measures are not difficult to foresee. In today’s world, civil aviation is not merely an industry; it constitutes critical infrastructure that facilitates the movement of millions of passengers, enables family reunification, provides access to medical treatment, allows the continuation of education, the pursuit of employment and economic activities, and facilitates the exercise of the freedom of movement. 

Depriving civilian populations of their rights and subjecting them to such harassment may, however, amount to collective punishment of protected persons under IHL when such coercive measures are imposed in the context of an IAC. Article 33 of the fourth Geneva Convention which prohibits collective penalties has been interpreted by the ICRC as 

“not limited to sentences of punishment handed down by a court but applies to penalties of any kind imposed by the authorities of a Party to the conflict on multiple persons or entire groups of persons […]. The term ‘penalties’ should thus be understood broadly to cover, for example, criminal sanctions, administrative measures, and other forms of harassment by the authorities”. (para. 2543) 

The ICRC provides more examples from the recent armed conflicts such as restrictions on electricity, fuel, food, water and medical supplies. (para. 2550; see also Report of the UN Commission of Inquiry on Syria which considers collective punishment through denial of freedom of movement, indiscriminate bombardment, denial of access to humanitarian aid, food, water, and medicine, prevention of leaving, and forced displacement, p.8) 

The ICRC indicates that the punitive purpose of the measure is the decisive criterion (para. 2547) and stipulates that: 

“[p]rovided that the punitive purpose requirement is met, the measures do not have to exceed any threshold of severity. For example, imposing general fuel restrictions in an occupied territory as a punitive reaction to attacks by enemy militants based in that territory would violate the prohibition of collective punishment even if alternative fuel sources were available and irrespective of the seriousness of the humanitarian impact”. (para. 2548) 

As reflected in the ICRC commentary, the official statement by the sanctioning party works as an indicator of the existence of the punitive purpose. (para. 2549) Apart from the literal meaning of the phrase “sanction”, such an indicator is repeatedly evident in statements made by the highest-ranking U.S. officials, including the incumbent U.S. President announcing sanctions as Iran failed to take the opportunity to make a deal. Against this background, characterizing the measures in question as a form of collective punishment would not appear particularly difficult from a legal perspective. (See also: here, here, and here)

While the imposition of a collective punishment is not listed as a grave breach of the Geneva Conventions or of the Additional Protocol I, collective punishment constitutes a war crime under customary international law. (paras. 2551& 2552; evidenced also by the practice of the SCSL, and also argued by scholars). Nonetheless, the United States’ ability to achieve its objective depends largely on the compliance of other States. This explains why US officials warn third States of the consequences they may face if they refuse to implement the secondary sanctions. Consequently, States subjected to such pressure may find themselves forced to choose between complying with U.S. sanctions and fulfilling their obligation under common Article 1 of the Geneva Conventions to ensure respect for IHL, including by refraining from actions that may contribute to violations of the Conventions or the commission of war crimes against civilians. (para. 224) 

The obligation to ensure respect as repeatedly referred to by the ICJ (see e.g. Advisory Opinion 19 July 2024 on Legal Consequences arising from the Policies and Practices of Israel in the Occupied Palestinian Territory, including East Jerusalem, para. 279) requires the State Parties to the Geneva Conventions to take all reasonable measures within their capacity to bring violations of the Conventions to an end and to exercise their influence to induce the offending Party to resume compliance with the Conventions. (para. 229) This, of course, entails that States Parties must refrain from encouraging, aiding, or assisting in violations of the Conventions. (para. 158) This obligation to abstain, however, should not be equated with the rules of attribution under the articles of responsibility of States (ARSIWA). As the ICRC has made it clear in its commentary, the  

“Common Article 1 and the rules on State responsibility thus operate at different levels. The obligation to ensure respect for the Conventions is an autonomous primary obligation that imposes more stringent conditions than those required for the secondary rules on State responsibility for aiding or assisting. What is at stake is more than aid or assistance to violations of the rules of international law but concerns aid or assistance to violations of rules whose observance the High Contracting Parties have specifically undertaken to respect and ensure respect for. Financial, material or other support in the knowledge that such support will be used to commit violations of humanitarian law would therefore violate common Article 1, even though it may not amount to aiding or assisting in the commission of a wrongful act by the receiving States for the purposes of State responsibility.” 

In the present context, this means that the obligation to ensure respect under common Article 1 is not confined to conduct that is directly attributable to the State under the rules of State responsibility. Hence, where ground-handling operations are carried out by private actors, or an airport is operated or managed by private entities, the State may nevertheless be required, by virtue of its obligation to ensure respect for the Geneva Conventions, to take appropriate measures to prevent persons or entities within its jurisdiction or subject to its authority or influence from engaging in conduct that would violate the Conventions. The relevant obligation therefore does not depend on whether the conduct in question is attributable to the State under the rules of State responsibility. Rather, it requires the State to use the means of influence and control available to it to prevent or bring to an end the violations of the Conventions by individuals or entities within its jurisdiction, and to refrain from facilitating such violations.

Conclusion

The current situation of war and heightened tensions between Iran and the United States, while affecting other States from various political, security, and economic perspectives, has tested some of the most fundamental foundations not only of international law but also of morality. Nowhere is this more starkly illustrated than in the threat to annihilate a country made in an address to the United Nations, an institution established to save humanity from the scourge of war.

The new wave of sanctions against Iranian civil aviation once again places States at an important crossroads: whether to uphold their vital obligation to preserve the rule of law at this particularly difficult time, or to contribute to the continued disregard of the fundamental principles of the international order, at the expense of millions of civilians who are already suffering the consequences.

Photo by Bao Menglong on Unsplash