At least nine civilians have been killed in fighting between Nato forces and the Taliban.
Nato said it happened when its forces battling Taliban fighters bombed a building inside Pakistan near the Afghan border early on Saturday.
The alliance said it was investigating the exact number of people killed and the toll might be higher.
"It's a response to an attack by insurgent forces," Nato spokesman Major John Thomas said on Monday. "That means the decision process is more rapid, and distinguishing targets is made under the heat of receiving fire from that position."
The incident is the latest in a rising number that have seen civilians killed or injured in crossfire in the country.
According to the Associated Press, 399 civilians were killed between January 1 and June 23, 203 of whom are thought to have been killed as a result of Nato action, 178 by Taliban fighters.
Over the weekend, Hamid Karzai, Afghanistan's president, denounced the Taliban for killing civilians, but also expressed outrage at the incidents involving Nato.
Separately, a bomb attack and gun battles across Afghanistan killed seven Afghan security forces and 15 suspected fighters, while a district the Taliban took over last week was recaptured in the volatile south, officials said on Monday.