Killed in action (KIA) is a casualty classification generally used by militaries to describe the deaths of their personnel at the hands of enemy or hostile forces at the moment of action. The United States Department of Defense, for example, says that those declared KIA did not need to have fired their weapons, but only to have been killed due to a hostile attack. KIAs include those killed by friendly fire during combat, but not from incidents such as accidental vehicle crashes, murder, or other non-hostile events or terrorism. KIA can be applied both to front-line combat troops and naval, air, and support forces.