A report about the Nov. 25 incident found that “inadequate coordination by U.S. and Pakistani military officers,” and erroneous map information provided by NATO to Pakistani authorities, were to blame for the battlefield blunder, which has added enormous strain to the already fraught relationship between Washington and Islamabad.

The lack of coordination and the incorrect mapping “resulted in a misunderstanding about the true location of Pakistani military units,” the Pentagon said in a statement issued early Thursday. “This, coupled with other gaps in information about the activities and placements of units from both sides, contributed to the tragic result.”

“For the loss of life — and for the lack of proper coordination between U.S. and Pakistani forces that contributed to those losses –we express our deepest regret,” the Pentagon said.