Unlawful Blockades as Crimes Against Humanity

Junteng Zheng
April 20, 2018


In December 2017, top officials of multiple UN agencies issued a joint statement, warning that the blockade of Yemen could lead to "one of the largest famines in modern times." The International Committee of the Red Cross (ICRC) reported that the blockade was hindering imports food, medicine, and fuel, and the risk of cholera was on the rise.[1] A blockade is a method of warfare that has long been used, but without much international legal scrutiny. To be clear, the use of blockades in armed conflicts is not unlawful per se, but they must be utilized in a manner consistent with international law. This Insight examines under what circumstances the use of blockades can constitute crimes against humanity.

Why "Crimes Against Humanity"?

Modern treaty-based international humanitarian law (IHL) focuses on states' responsibility. It prohibits deliberate starvation as a war tactic in international armed conflicts (IACs)[2] and in some non-international armed conflicts (NIACs).[3] Denying humanitarian access is prohibited under Geneva Convention IV, which only governs IACs.[4] Additional Protocol II leaves it subject to the consent of state(s) concerned and does not mandate such obligation in NIACs[5] —consequently, violating this rule is generally not considered a "grave breach" that entails criminal responsibility.

Customary IHL, governing both state and non-state actors, prohibits deliberate starvation and impediment of humanitarian relief, regardless of conflict classification.[6] Though even when the violations constitute war crimes under customary international law, the key obstacle to accountability is finding a court with proper jurisdiction. The Rome Statute of the International Criminal Court (ICC) explicitly lists starvation and barring humanitarian relief as prosecutable war crimes when committed in IACs but is silent as to NIACs.[7] Due to this jurisdiction limitation, starvation and impediment of humanitarian relief are unlikely to be prosecuted as war crimes before the ICC when committed in NIACs.

This leaves an impunity gap in punishing blockades that cause mass starvation and deprivation of humanitarian relief; however, prosecuting such circumstances as crimes against humanity potentially offers a solution. First, crimes against humanity can be charged regardless of whether there is an armed conflict, or whether it is an IAC or a NIAC. Second, while some relevant actors might not be states parties to the ICC, establishing the commission of crimes against humanity opens the door for a Security Council referral, without having to tackle jurisdictional limit on prosecutable war crimes before the ICC.Third, crimes against humanity can be prosecuted using universal jurisdiction—responsible individuals can be prosecuted before any court (international, regional, or national) with jurisdiction over crimes against humanity. 

Undoubtedly, blockades that cause mass starvation and deprivation of humanitarian relief can constitute both war crimes and crimes against humanity. Their prosecution is not mutually exclusive. The conviction of either is also not superior to the other. And blockades do not necessarily entail mass starvation or lack of humanitarian relief. The following sections examine under what circumstances a blockade would constitute crimes against humanity. 

Applicable Law and Analysis 

Crimes against humanity refer to certain acts "when committed as part of a widespread or systematic attack directed against any civilian population, with knowledge of the attack."[8] The specific punishable "acts"are listed in Article 7(1), among which "extermination" and "other inhumane acts" are relevant to our discussion.


The Rome Statute defines "attack" as "course of conduct involving the multiple commission of acts referred to in paragraph 1 [of article 7]." Extermination includes "infliction of conditions of life, inter aliathe deprivation of access to food and medicine, calculated to bring about the destruction of part of a population."[9] The key issue is whether imposing blockades can amount to an "attack" for these purposes, and thus constitute "extermination."

An "attack" can be perpetrated as an affirmative violent act or as a result of legislation and government policy.[10] It does not have to be a "military attack"—"any mistreatment of the civilian population" could suffice, including non-violent acts.[11] Particularly, extermination can be committed "either directly, such as by killing the victim with a firearm orless directly, by creating conditions provoking the victim's death."[12] As M. Cherif Bassiouni echoed: extermination could occur with either a kinetic act of "firing a rifle or wielding a knife" or imposing "conditions of life amenable to mass killing."[13]

This interpretation is coherent, read together with the text of the Rome Statute, because other acts of non-violent/non-kinetic nature are also enumerated in Article 7 as punishable acts, like imposing apartheid or pressuring civilians to act in a particular manner.[14] In fact, the "Elements of Crimes" goes even further and includes "omission" as a form of "attack."[15] As such, whether an act constitutes an "attack" under crimes against humanity is determined on the essence of its natureandimpact upon civilians, rather than whether it is violent/kinetic at its appearance.

With respect to a blockade, the fact that restrictions of resources themselves were not kinetic acts does not mean they fall outside the meaning of an "attack" for purposes of crimes against humanity. The acts of embargo, when conducted in a manner that cause deprivation of resources indispensable to survival, including food, medicine, sanitation, electricity, and fuel, among others—could constitute an attack. While such deprivation did not instantly translate into deaths, it imposed excessive burdens upon civilians that eventually caused great loss of life. The duration of time between the infliction of conditions and the death is irrelevant for establishing the offense. 

The less clear issue is whether the intent—"bring about the destruction of part of a population"—is met. The mental element has two parts: for a crime that requires conduct, the perpetrator must intend to engage in the conduct; for a crime that requires a consequence, the perpetrator must mean to cause the consequence orbe aware that it will occur in the ordinary course of events.[16] "Ordinary course" means that it is assessed with an objective standard—the perpetrator's subjective belief is irrelevant. The ICC has adopted a "virtual certainty" test in assessing the foreseeability—the consequence would normally follow in light of the circumstances where the acts were committed.[17]

Under one view, a blockade is only intended to cut off weapons or resources supplied to adversarial military forces, not to target civilians—any impediment of humanitarian access is only incidental harm. This justification was invoked in the Yemen blockade, as well as the Gaza blockade (2007–2010) and the Ghouta blockade (2013–arguably present). However, relevant actors knew of those situations based on intelligence collected—an ordinary person with similar knowledge to relevant actors, in a similar situation, can and should reasonably foresee such consequences if the blockades continue. The mental element is likely to have been met in this context. But ultimately, the outcome of the mental element assessment depends on how the courts will read the "intent" and "virtual certainty" test vis-à-vis blockades. 

"Other inhumane acts" 

Article 7(1)(k) of the Rome Statute provides a residual category of "[o]ther inhumane acts of similar character intentionally causing great suffering, or serious injury to body or to mental or physical health." Inhumane acts that fall under crimes against humanity may potentially include deprivation of basic food, medical treatment, and minimum sanitary conditions.[18] Famine and breakouts of disease have indeed long been documented in conflicts. But blockades imposed in situations like Yemen, Gaza, or Ghouta would substantially increase the severity and scale of the already existing crisis.

This Insight will next analyze whether an unlawful blockade can meet the general requirements of crimes against humanity, namely the three "chapeau" elements:

1.     committed as part of a widespread or systematic attack; 

2.     directed against any civilian population pursuant to or in furtherance of a State or organizational policy; and 

3.     committed with knowledge of the attack.

"Widespread or systematic"

The "widespread or systematic" prong has been interpreted as two disjunctive requirements, meaning that with either satisfied, this element is met. "Widespread" refers to the large-scale nature of the attack. It is not to be evaluated with any specific numerical threshold, but on a contextual basis, including the social context, geographical varieties, and so on.[19] "Systematic" refers to the organized nature of the acts and "the improbability of their random occurrence"—typically reflected in a pattern or methodical plan of acts.[20]

A blockade is usually operated in a manner that is both widespread and systematic. It very often covers a large area of territory, affecting a large civilian population (millions have been severely depleted basic living needs in the case of Yemen). The use of blockade also requires well-organized plans to carry out repetitive and continuing restrictions over resources going into the controlled area. Restrictions imposed through a blockade, in their nature, are unlikely to be random occurrence—it requires a methodical mechanism for enforcement. 

"State or organizational policy"

This element requires that a state or organization planned to commit an attack, precluding isolated or random individuals' acts. It is satisfied not only when someone actively promotes the policy, but also when someone commits acts envisaged in the policy.[21] It can be by a government or any type of group that has the capacity to carry out the attack—making it possible to hold non-state actors accountable.[22] This, however, does not require the "policy" to have a specific rationale or be formally adopted. It can be implemented by action or inaction, and can be inferred from the circumstances.[23]

A blockade can only be implemented with actions set out in pre-planned policy/guidelines, through forces of a government or non-state group. For example, in Yemen, blockades have been imposed by both a Saudi-led coalition and some local armed groups, though at different scales. The systematic and consistent restrictions of resources on a large scale cannot be achieved through isolated individual acts. Considering the scale, duration, and intensity of blockades, this "chapeau" element is usually met with either clear evidence of policy or at least inference from circumstantial evidence. 

"Knowledge of the attack"

The "knowledge of the attack" element requires that perpetrators have knowledge of an attack on the civilian population and that their act is part of the attack, but it does not require perpetrators to fully understand the exact nature or scale of the attack.[24] With the widespread reporting on the crisis in Yemen, one can hardly deny having knowledge of the "attack" and its consequences. Furthermore, relevant actors knew that the blockade occurred in an overall situation of armed conflict, where other attacks against civilians in violation of international law had already occurred. In this context, actors restricting humanitarian relief not only knew of the overarching policy of the blockade, but also of other attacks against civilians and the overall impact.


Although blockades are permitted when carried out in a manner consistent with international law, when they do constitute an international crime, it is critical for the international community to accurately recognize and name it as such. Doing so defends the integrity of international law by acknowledging and condemning violations, and also galvanizes international attention, which can facilitate appropriate responses. Further, it offers legal basis to hold either states or non-state actors accountable when the prohibited acts occur in NIACs or even non-conflict situations. Overall, considering the complexity of the nature of armed conflicts today, establishing the commission of crimes against humanity provides a greater prospect for accountability.

About the Author:Junteng Zheng is a practicing international lawyer based in New York City, focusing on international criminal law and human rights. Zheng is pursuing his graduate research and studies as a Mark Haas Fellow at Columbia Law School. He is also the 2017–2018 Arthur C. Helton Fellow with ASIL.

[1] Yemen: As Threat of Famine Looms, UN Urges Saudi-Led Coalition to Fully Lift Blockade of Red Sea Ports, UN News(Dec. 2, 2017), http://www.un.org/apps/news/story.asp?NewsID=58209#.WnOMp2aZPOT; Yemen: Border Closure Shuts Down Water, Sewage Systems, Raising Cholera Risk, ICRC (Nov. 17, 2017), https://www.icrc.org/en/document/yemen-border-closure-shuts-down-water-sewage-systems-raising-cholera-risk.

[2] Protocol Additional to the Geneva Conventions, relating to the Protection of Victims of International Armed Conflicts art. 54(1),June 8, 1977, 1125 U.N.T.S. 3.

[3] Protocol Additional to the Geneva Conventions, relating to the Protection of Victims of Non-International Armed Conflicts, art. 14, June 8, 1977, 1125 U.N.T.S. 609 [Additional Protocol II].

[4] Geneva Convention Relative to the Protection of Civilian Persons in Time of War art. 23, Aug. 12, 1949, ‎75 U.N.T.S. 287.

[5] Additional Protocol II, supra note 3, art. 18(2).

[6] Customary IHL Database, Rules 53, 55, ICRC, https://ihl-databases.icrc.org/customary-ihl/eng/docs/v1_rul (last visited Apr. 19. 2018).

[7] Rome Statute of the International Criminal Court, arts. 8(2)(b)(xxv), 8(2)(c), 8(2)(e), July 17, 1998, 2187 U.N.T.S. 90 [hereinafter Rome Statute].

[8] Id. art. 7(1).

[9] Id. art. 7(2).

[10] See William Schabas, The International Criminal Court: A Commentary on the Rome Statute(2010).  

[11] Prosecutor v. Katanga,ICC-01/04-01/07, Judgment, ¶1101 (Mar. 7, 2014). 

[12] Prosecutor v. Krstić, IT-98-33-T, Judgment, ¶ 499 (Aug. 2, 2001); Prosecutor v. Rutaganda, ICTR-96-3-T, Judgment and Sentence, ¶¶ 83–84 (Dec. 6, 1999).

[13] Arguments can be made that creating "conditions of life amenable to mass killing" is by definition "violent" because deaths are caused. Here, Bassiouni noted the subtle difference between: 1. acts that are violent/kinetic on their face and 2. acts that are essentially violent. The initial act or policy of placing a blockade in itself is not kinetic, but it can be essentially violent where it creates conditions amenable to killing. 

[14] Rome Statute, supra note 7, arts. 7(2)(d), 7(2)(h).

[15] Elements of Crimes,  International Criminal Court5 (2011), available at https://www.icc-cpi.int/NR/rdonlyres/336923D8-A6AD-40EC-AD7B-45BF9DE73D56/0/ElementsOfCrimesEng.pdf.

[16] Rome Statute, supra note 7, art. 30.

[17] Prosecutor v. Bemba, ICC-01/05-01/08, Decision, ¶ 362 (June 15, 2009).

[18] David Marcus, Famine Crimes in International Law, 97 AJIL 245, 271–79 (2003).

[19] International Law Commission, Report on the Work of Its Sixty-Ninth Session, U.N. Doc. A/72/10, ch. IV, 1–63 (2017).

[20] Prosecutor v. Kunarac, Case No. IT-96-23-T & IT-96-23/1-T, Judgment, ¶429 (Feb. 22, 2001). 

[21] Prosecutor v. Bemba, ICC-01/05-01/08, Judgment, ¶ 161 (June 15, 2016).

[22] Katanga, supra note 14, ¶1119

[23] Id. ¶¶ 1108–09, 1113.

[24] Elements of Crimes, supra note 15, at 9.