U.S. Failed to Stop Attack in Jordan After Mix-Up Over Drone Identity

The U.S. failed to stop a deadly attack on an American military outpost in Jordan when the enemy drone approached its target at the same time a U.S. drone was also returning to base, U.S. officials said Monday.

The return of the U.S. drone led to some confusion over whether the incoming drone was friend or foe, officials have concluded so far, though they cautioned the inquiry into the attack was in an early stage.

The enemy drone was launched from Iraq by a militia backed by Tehran and struck the outpost’s...