Both Hamas's attack on Israel on October 7 and Israel's subsequent relentless bombardment of the Gaza Strip have provoked international condemnation, many claiming both sides have committed war crimes. But what exactly are we talking about? What are warring nations allowed, or not allowed, to do – and who decides?

International humanitarian law is a set of rules that seek to limit the effects of armed conflict, and they lay out the rules of war. It's made up of several founding texts, the most important of which are the four Geneva Conventions. They set out the fundamental principles of war: the distinction between civilians and combatants, proportionality in attack, precautions in attack and the prohibition of unnecessary suffering. Any "serious violation" of these rules is considered a war crime.