Criminal responsibility in the context of "War crime"

A war crime is a serious violation of the laws and customs applicable in armed conflict, known as international humanitarian law (IHL) and the laws of war, which gives rise to criminal responsibility under international law. Examples of actions committed by combatants in the conduct of war that can give rise to individual criminal responsibility include, but are not limited to: intentionally killing civilians, torture, taking hostages, unnecessarily destroying civilian property, deception by perfidy, wartime sexual violence, pillaging, the granting of no quarter despite surrender, the conscription of children in the military, ordering any attempt to commit mass killings (including genocide or ethnic cleansing), and flouting the requirements of distinction, proportionality and military necessity.

The formal concept of war crimes emerged from countries fighting and the codification of the customary international law that applied to warfare between sovereign states, such as the 1863 Lieber Code of the Union Army in the American Civil War and the Hague Conventions of 1899 and 1907 for international war. In the aftermath of the Second World War, the war crime trials of the leaders of the Axis powers established the Nuremberg principles, such as that international criminal law defines what is a war crime. In 1899, the Geneva Conventions legally defined new war crimes and established that states could exercise universal jurisdiction over war criminals. In the late 20th century and early 21st century, international courts extrapolated and defined additional categories of war crimes applicable to a civil war.