Friendly fire

Friendly fire is when a soldier accidentally injures or kills someone from their own military or a soldier who is on neither side. If civilians are killed and not soldiers, it is called collateral damage.

According to Paul R. Syms, friendly fire is a very old phenomenon. He cites early descriptions of conflicts and events that were documented in Ancient Greece. He and other historians also point out that friendly-fire losses were significantly enhanced by weaponry like firearms, artillery, and airplanes.