A weapon fired by the International Security Assistance Force (Isaf) hit a building in Pakistan as warplanes were chasing down insurgents preparing to attack a base across the Afghan border Saturday, a spokesman said.

Residents said a child, a woman and seven men were killed. Pakistan military spokesman Major General Waheed Arshad said his government had protested and demanded an explanation. He said a rocket had struck the building.

"We have reports that one of our weapons hit a building which may have had a number of civilians in it and that building may have been a home or way-station or some hotel facility," Isaf spokesman Major John Thomas told AFP.

"We regret the loss of innocent life," he said.

Isaf said earlier up to 60 militants were killed in the operation, which spanned the border in Afghanistan's southeastern Paktika province and Pakistan's North Waziristan tribal area.

In Kabul Saturday, Karzai accused Isaf and the separate US-led coalition of causing civilian casualties in the battle against insurgents through "indiscriminate and unprecise" operations.

There was an "extreme use of force" and action was not being coordinated with Afghan forces despite repeated complaints over several years, the president said.

A Nato spokesman said the president's anger was understandable.

"But let's make clear that no Isaf soldier intends to kill civilians," Nicholas Lunt said in Kabul. "That's not the case with Taliban. They deliberately kill civilians."