On November 26 a NATO airstike along Pakistan's border with Afghanistan killed two dozen Pakistani solders.
Pakistan responded by cutting supply routes into Afghanistan and pulling out of an international conference in Germany next week on Afghanistan's future.
Amid finger pointing and suspicion the investigations into the incident goes on.
U.S. Military spokesman Captain John Kirby was questioned about the attack at a Pentagon news conference.
SOUNDBITE: U.S. Military spokesman Captain John Kirby, saying (English):
"In this case, this was clearly a military engagement. It is under investigation, and we are going to let that investigation proceed, and we are going to go from there."
REPORTER ASKING (OFF-CAMERA):
"You are suggesting that this was a military engagement on the part of Pakistan?"
SOUNDBITE: U.S. Military spokesman Captain John Kirby, saying (English):
"Clearly. Look, well it was a military engagement in that cross-border fire resulted in the death of some two dozen Pakistani soldiers - not innocent villagers or civilians."
REPORTER ASKING (OFF-CAMERA):
"Do you believe that any of that fire came from Pakistani soldiers, rather than insurgents, which is why U.S. called in the air strikes.
SOUNDBITE: U.S. Military spokesman Captain John Kirby, saying (English):
"Not going to get into the details. It is under investigation. We are going to let that proceed."
Outrage over the attack has spilled into the streets in Pakistan.
SOUNDBITE: U.S. Military spokesman Captain John Kirby, saying (English):
"We've expressed our remorse and regret for the loss of life at the highest levels of this department, and at other agencies as well. What we aren't going to do is to get into fixing blame or fault right now. There is an investigation going on. We need to let that investigation proceed, let the facts take us where they may, and as George said, we continue to invite the Pakistanis to participate in that investigation."
The NATO attack shifted attention away from Pakistan's widely questioned performance against militants who cross its border to attack U.S. and other NATO forces in Afghanistan.
NATO hopes an investigation it promised will defuse the crisis and that confidence-building measures can repair ties.
Deborah Lutterbeck, Reuters