At least 12 civilians were killed in an air strike on a religious school in the northern Afghan province of Takhar.
They said the strike on the madrassa in the village of Hazara Qurluq killed 11 children and their prayer leader.
Doctors at a hospital close to the site of the air strike in the provincial capital Taloqan said the majority of victims brought in were children, and Mohammad Jawad Hejri, a spokesman for the provincial governor, also said the strike had killed children.
But Afghan government officials denied the reports that children had been killed, saying only Taliban fighters died. The Ministry of Defence did not deny that the strike hit a school.
The fighting came despite assurances from Taliban officials to the US that violence would be scaled back to facilitate historic peace talks between the Afghan government and the Taliban.
Violence between government forces and the Taliban has worsened in recent weeks in Afghanistan.
The strike came after more than 30 security force members were killed in a major Taliban ambush in the province.