The air strikes on November 26, at two remote border posts in Mohmand tribal area near the Afghan border, have enraged Pakistan.
Western media reports have quoted unnamed Afghan officials as saying that a joint NATO-Afghan force on the Afghan side of the border received incoming fire from the direction of the Pakistani posts and called in the air strikes.
Major General Athar Abbas, Pakistan's chief army spokesman, has rejected the claims, saying NATO and Afghanistan were "trying to wriggle out of the situation by making excuses."
He said the strikes lasted almost two hours and continued even after local commanders had asked NATO to stop the attacks.
NATO has apologized for what it called a "tragic unintended incident" and has promised an investigation.
Islamabad said it was closing key supply routes for U.S.-led troops in Afghanistan and demanded that Washington leave a base used by American drones. Interior Minister Rehman Malik said his ministry would ensure that the supply route remained shut down.
compiled from agency reports