一名美官员称， 当时有一架美军无人机正返航， 基地人员误以为来袭无人机为己方所有， 没有拦截。
调查仍在继续， 为何敌我识别装置没起效， 敌人如何了解美军无人机起降时间， 是否因为太过有规律的时间和航线
原文：The return of the U.S. drone led to confusion over whether the incoming drone was friend or foe, officials have concluded, though they cautioned the inquiry into the attack was in an early stage.
调查仍在继续， 为何敌我识别装置没起效， 敌人如何了解美军无人机起降时间， 是否因为太过有规律的时间和航线
原文：The return of the U.S. drone led to confusion over whether the incoming drone was friend or foe, officials have concluded, though they cautioned the inquiry into the attack was in an early stage.
