Explainer
Sieges, Blockades and Starvation: What International Law Says
Sieges and blockades are not governed by a single simple rule. The key questions include starvation, civilian protection, humanitarian relief and the conduct of hostilities.
Reviewed 18 September 2026. This is an evergreen explainer; case-specific legal findings should be checked against the newest authoritative source.
In short: Sieges and blockades are not governed by a single simple rule. The key questions include starvation, civilian protection, humanitarian relief and the conduct of hostilities.
Sieges and blockades can isolate territory, restrict movement and cut supply routes. International humanitarian law does not treat every siege or blockade as automatically unlawful, but it imposes important restrictions—especially the prohibition on starving civilians as a method of warfare and the duties connected to humanitarian relief.
Starvation of civilians is prohibited
IHL prohibits starvation of the civilian population as a method of warfare. Parties may not deliberately deprive civilians of objects indispensable to survival—such as food and water—for the purpose of starving them. The protection applies even when fighters are also present in the besieged area.
Civilians remain protected inside a besieged area
Remaining in a besieged city does not turn a civilian into a combatant. Civilians retain protection against direct attack unless and for such time as they directly participate in hostilities. Their presence also remains relevant to proportionality and precautions in attack.
What about evacuations?
The rules are fact-specific. The ICRC has stressed that civilians caught in besieged areas must be allowed to leave, while evacuations must also comply with applicable protections, including humane treatment and prohibitions on unlawful forced displacement. A theoretical route is not meaningful if movement is not genuinely safe or feasible.
Humanitarian relief is not optional rhetoric
Parties to a conflict have primary responsibility to meet the basic needs of civilians under their control. Where civilians lack essential supplies, IHL contains rules on impartial humanitarian relief operations. Consent and security arrangements matter, but access cannot simply be manipulated to achieve an unlawful starvation strategy.
Blockades raise additional bodies of law
A naval blockade is a specific concept with rules developed in the law of armed conflict at sea, while land sieges are governed through broader IHL rules. Political debate often uses “blockade” more loosely for sanctions, border closures or access restrictions, so reports should define what measure is actually being discussed.
What investigators look for
Legal analysis may examine policy documents, public statements, the design and duration of restrictions, availability of alternatives, treatment of relief consignments and the foreseeable effects on civilians. A humanitarian catastrophe can be evidence relevant to the analysis, but the exact legal character still depends on the applicable rule and facts.
Frequently asked questions
Are all sieges illegal?
No. But siege warfare is constrained by rules protecting civilians, including the prohibition on starvation as a method of warfare.
Can food be withheld because fighters also consume it?
The law does not permit starving a civilian population as a method of warfare simply because enemy fighters are present.
Is a humanitarian corridor a substitute for civilian protection?
No. Safe passages can help, but the ordinary protections of IHL continue to apply regardless.