friendly fire

Friendly fire is an attack by a military force on friendly forces while attempting to attack the enemy, either by misidentifying the target as hostile, or due to errors or inaccuracy. Fire not intended to attack the enemy, such as negligent discharge and deliberate firing on one's own troops for disciplinary reasons, is not called friendly fire. Nor is unintentional harm to non-combatants or structures, which is sometimes referred to as collateral damage.