A NATO air strike in southern Afghanistan early on Friday killed 25 civilians, including nine women and three young children, a provincial police chief said.
About 20 Taliban were also reported killed in the air strike shortly after midnight in Helmand province, police chief Colonel Mohammad Hassan said.
It was called in after Taliban fighters opened fire on a convoy of NATO's International Security Assistance Force (ISAF) from among houses and gardens in a village, he said.
"The NATO forces' air strike on the area mistakenly targeted two to three civilian houses, killing 25 civilians," Hassan said.
He said the dead included nine women and three children aged from six months to two years old. The rest were men, including the mullah of the mosque of the village, called Kunjak, he said.
ISAF said there had been an engagement in the area which had resulted in a number of victims.
"We don't know at the moment who these victims were and how many there were," spokesman Major John Thomas said.
Hassan said the bodies of the dead were lying where they had been hit.
The information that 20 Taliban were killed had come from "reports we get from the area and from the locals," he said. "The militants seem to have taken the Taliban bodies with them."
A spokesman for the insurgent Taliban, Yousuf Ahmadi, confirmed fighters from the group had ambushed troops in the area.
He claimed that eight foreign and Afghan soldiers were killed but this was not confirmed. The movement often exaggerates the figures for security forces' casualties.