The White House says senior U.S. civilian and military officials have extended condolences to their Pakistani counterparts following a NATO airstrike that Pakistan says killed 24 of its troops along a frontier area that serves as a haven for militants.
The unidentified officials also expressed a desire to work with Pakistan to investigate the deaths.
Friday night's airstrike dealt a huge blow to American efforts to rebuild its strained relationship with Pakistan.
In turn, Pakistan on Saturday blocked vital supply routes for U.S.-led troops in Afghanistan and demanded that the U.S. leave a base used by American drone aircraft within 15 days.
The White House statement did not address Pakistan's decision to block supply routes for the war in Afghanistan or its demand that the U.S. to vacate the base.