■ Siege

iege is a method of warfare carried out on land which is characterised by the encirclement of a locality or area, leading to its isolation, followed by attacks to crush its resistance while the term ‘blockade’ refers to a military operation, whether maritime or aerial, that cuts off or prevents all transport to a given area. In accordance with the rules and principles of international humanitarian law (IHL) and like for all other methods of warfare, a siege shall only be directed against enemy armed forces and not against the civilian population. The objective of a siege is to prevent the opposing armed forces from undertaking any movement or to cut them off from support and supply channels, thereby forcing them to surrender. Therefore, any siege that impedes the civilian population’s access to humanitarian aid is prohibited.

There is no explicit definition of a siege in IHL. However, there are general and specific rules for the protection of civilians in situations of armed conflict that apply during the period of siege and in the event of an attack on the besieged territory. The most significant of these relate to the prohibition of starvation of civilians and the right of civilians to receive humanitarian assistance as well as the possibility of evacuating of the most vulnerable.

The rights of the besieged populations (non-combatants, civilian population) that are under siege are as follows:

• diplomatic agents and citizens of neutral States must be granted the right to leave, unless fighting is in progress;
• evacuation of the wounded and sick from besieged areas is supported by IHL provisions which require parties to a conflict to endeavour to conclude local agreements for the evacuation of the wounded, sick, infirm and pregnant women from besieged areas. Such agreements must also provide for the safe passage of medical and religious personnel and medical materials within to such areas. (Common art. 3(2) of the GCs; GCI, art. 15; GCII, art. 18; GCIV, arts. 17 and 23; API, art. 70; APII, art. 18(2) and CIHL, rule 55).
• IHL does not encourage the evacuation of the civilians from besieged areas, but rather prohibits the use of forcible transfer of population as a method of warfare. (GCIV, arts. 49 and 147; APII, art. 17; CIHL, rule 129). Forcible displacement of civilians also constitutes a war crime under international criminal law in both international and non-international armed conflicts (arts. 8(2)(b)(viii) and 8(2)(e)(viii) of the Rome Statute). Even when voluntary evacuation is offered to civilians, those who refuse to leave a besieged area retain their status and rights, without forfeiting the protection afforded to civilians by IHL.
• IHL contains additional provisions on access to humanitarian assistance that apply in both situations of international and non-international armed conflict.
• the use of starvation of civilians as a method of combat is prohibited by IHL in all situations of armed conflict; (API, art. 54(1); APII, art. 14 and CIHL, rule 53). It is important to note that there is no exception for “imperative military reasons” for this method of combat in IHL;
• the use of starvation to force the civilian population’s movement is also prohibited. (API, art. 54(3)(b));
• the free passage of relief that is exclusively humanitarian and impartial and indispensable for the survival of the civilian population, is a conventional and customary rule of IHL applicable in all situations of armed conflict. Parties to the conflict cannot arbitrarily withhold it. The parties involved in an armed conflict must allow and facilitate the rapid and unimpeded passage of humanitarian assistance for civilians in need. The relief must be impartial in character and conducted without any adverse distinction, subject to their right of control. The passage of relief that is exclusively humanitarian and impartial in nature is indispensable for the survival of the civilian population. (GCIV, arts. 23 and 59; API, arts. 70-71; APII, art. 18(2) and CIHL, rules 55 and 56).
• A siege that result in the starvation of a civilian population (in particular through the deliberate denial of humanitarian assistance) is explicitly considered a war crime under the jurisdiction of the ICC only in the context of an international armed conflict (art. 8(2)(b)(xxv) of the Rome Statute). In 2019, the Assembly of States Parties to the Rome Statutes adopted an amendment to the definition of war crimes that includes the act of starvation of civilians in the context of non-international armed conflict (NIAC). The new article (8)(2)(e)(xix), prohibits as a war crime in NIAC, the intentional use of starvation of civilians as a method of warfare by depriving them of objects indispensable to their survival, including the willful impeding of relief supplies. However, this amendment is only applicable to the 16 States that have accepted it as of august 2024. Despite the limited effect of this amendment in most NIAC, such practices may also be prosecuted as inhumane treatment or crimes against humanity such as persecution or extermination, if they meet the criteria of the ICC definition, regardless of the existence or qualification of the armed conflict.
• In the event of an attack on a besieged locality, medical units, cultural property as well as civilian population and other persons protected by IHL must be spared (API, arts. 51(5)(b), 57 and 58; CIHL, rules 15-24). Moreover, the whole besieged area may not be treated as one single military objective (API, art. 51(5)(a)). Pillaging of the locality after its conquest is also forbidden (GCI, art. 15; GCII, art. 18 and GCIV, art. 16).

Despite the regulation of siege by IHL, there have been many instances where blockades and sieges have restricted access to essential supplies for civilian populations, particularly in situations of non-international armed conflict where the argument of State sovereignty is abused to deny impartial relief to populations living in areas disputed or controlled by non-State armed groups.

In response to this alarming military practice, decisions of international tribunals and resolutions of the United Nations Security Council (resolutions 688(1991); 2414(2011); 2139(2014); 2165(2014); 2216(2015); 2258(2015); 2332(2016); 2393(2017); 2401(2018); 2417(2018); 2449(2018); 2451(2018); 2504(2020); 2573(2021); 2717(2023); 2720(2023) and 2728(2024) have confirmed the prohibition of restricting humanitarian assistance in situations of siege and blockade.

➔ Blockade ▸ Evacuation ▸ Famine ▸ International Court of Justice ▸ International Criminal Court ▸ Methods (and means) of warfare ▸ Protected persons ▸ Protecting powers ▸ Relief ▸ Right of Access ▸ War Crimes/Crimes against Humanity

The legality of siege warfare gained significant attention following the siege of Sarajevo (from April 1992 to February 1996) during the armed conflict resulting from the dissolution of the former Yugoslavia. In the*Galić case, the accused, who was the commander of the Bosnian Serb unit that encircled the city of Sarajevo, was indicted for his role in a shelling and sniping campaign of the capital of Bosnia-Herzegovina. The Trial Chamber of the ad hoc International Criminal Tribunal for the former Yugoslavia (ICTY) convicted Galić of “inflicting terror” on the civilian population in “violations of the laws and customs of war.” (API, article 51 and APII, article 13). ( Prosecutor v. Galić , Case no. IT-98-29-T, Judgment and Opinion, 5 December 2003, para. 769).

In summary, a limited number of decisions issued by international tribunals, including the ICTY, the ICJ and the ICC, provide further insight into the concept of siege. It is evident that international courts have yet to provide further explanations regarding the elements that should be taken into consideration when examining a siege situation in relation to both IHL and international criminal law (ICL). The involvement of the ICJ and the ICC in investigating war crimes and crimes against humanity committed during the conflict between Israel and the Hamas in the Gaza Strip in 2024 could result in the issuance of pertinent decisions on this topic in the coming years.**

Study on Customary IHL* , 2005, Rule 53, Starvation as a Method of Warfare. Available at https://ihl-databases.icrc.org/en/customary-ihl/v1/rule53