As many as 14 people, including women and children, were killed in an air strike carried out during an operation by Afghan security forces near the northern city of Kunduz, officials said.
Afghan officials said the incident was still being investigated and it was unclear whether the casualties had been caused by Afghan or US aircraft, both of which flew missions in support of the operation. A statement from the US military said there was no indication that its aircraft were responsible.
The civilian deaths add to a total that reached record levels in the first half of the year, according to a United Nations report this week that noted a sharp jump in casualties from air strikes.
Nematullah Temori, a spokesman for the Kunduz governor, said women and children were among 14 people killed in the raid in Chardara, a district outside Kunduz city.