KABUL, Afghanistan — An investigation into a NATO attack that killed 24 Pakistani troops last month near the Afghan border has concluded that a combination of mistrust and bad maps led to the airstrikes on two Pakistani outposts, the U.S. Department of Defense and a NATO official said today.

“The report says we recognize we made mistakes, and that mistakes were also made by the Pakistanis,” said the NATO official, who could not be named because the Defense Department’s investigation has not yet been made public.

“We have a lot of work to do to improve coordination, and we’ve already implemented steps to do that,” the official said.

The Defense Department said in a statement today that the investigation found U.S. forces — given what information they had available to them at the time — reacted in self-defense and with appropriate force after being fired upon from the direction of the Pakistani border in the Nov. 26 incident.

“Inadequate coordination by U.S. and Pakistani military officers operating through the border coordination center — including our reliance on incorrect mapping information shared with the Pakistani liaison officer — resulted in a misunderstanding about the true location of Pakistani military units,” said the statement.

“This, coupled with other gaps in information about the activities and placement of units from both sides, contributed to the tragic result,” it said.

NATO, Afghanistan and Pakistan forces use the joint border control centers to share information and coordinate security operations.

Since the Nov. 26 attack on the Pakistani military outposts on the border between Afghanistan and Pakistan in mountainous east Kunar province, a furious Pakistani government has shut down NATO supply routes to Afghanistan and thrown the U.S. out of its Shamsi Air base in southwestern Baluchistan province.