WASHINGTON (AP) — The deaths of five Americans killed in a U.S. airstrike in Afghanistan stand as a fresh reminder of the dangers of friendly fire, an element of war that is older than the nation.

In 1758, during the French and Indian War, a detachment of the British Army led by Col. George Washington got into a firefight with a fellow infantry unit that had arrived to offer assistance. At dusk on a foggy day, they apparently mistook each other for French forces, and at least 13 British troops were killed.