The official said Thursday that mistakes were made both by NATO and Pakistani forces.

The official said a company-sized U.S.-Afghan commando unit operating on the Afghan side of the border in eastern Kunar province came under fire from the direction of Pakistan.

The official said mistakes were made when they attempted to determine whether there were any Pakistani positions in the vicinity in order to safely return fire.

Different mapping systems then led to mistakes and airstrikes on two Pakistani outposts.

The official could not be named because the report has not yet been made public.