friendly fire
noun [ U ] military specialized uk/ˌfrend.li ˈfaɪər/ us/ˌfrend.li ˈfaɪr/
（战争中）误伤自己人的火力，来自友军的炮火
during a war, shooting that is hitting you from your own side, not from the enemy
Three soldiers were killed by friendly fire when a mortar bomb hit their truck. 一发迫击炮弹击中了自己人乘坐的卡车，有3名士兵被炸死。
Compare: blue-on-blue