To be entitled to prisoner-of-war status, captured persons must be lawful combatants entitled to combatant's privilege—which gives them immunity from punishment for crimes constituting lawful acts of war such as killing enemy combatants. To qualify under the Third Geneva Convention, a combatant must be part of a chain of command, wear a "fixed distinctive marking, visible from a distance", bear arms openly, and have conducted military operations according to the laws and customs of war. (The Convention recognizes a few other groups as well, such as "nhabitants of a non-occupied territory, who on the approach of the enemy spontaneously take up arms to resist the invading forces, without having had time to form themselves into regular armed units".)