In the latest incident, a Western official and a senior Afghan security official said NATO and Afghan forces had come under fire from across the border with Pakistan before NATO aircraft attacked a Pakistani army post, killing the soldiers.
“They came under cross-border fire,” the Western official said, without identifying the source of the fire.
The Afghan official said troops had come under fire from inside Pakistan as they were descending from helicopters, which had returned fire.
Both officials asked not to be named because the attack is so sensitive.
Pakistan has said the attack was an unprovoked assault and has said it reserves the right to retaliate.