By Charles Haviland
BBC News, Kabul
At least 15 civilians have been killed in an offensive by Nato and Afghan forces in the southern Helmand province, according to local police.
Nato said there was no substantial evidence of civilian deaths
The Afghan government earlier said a large number of Taleban fighters died in Thursday's raid in Sangin district.
But the district police chief, Gholam Wali Jan, told the BBC that half of the 30 people killed were civilians.
Local people put the death toll higher. A spokesman for Nato in Helmand said it had no evidence to support the claim.
The spokesman for British forces, who are leading the offensive in Helmand, said there was no substantial evidence of such deaths and that the forces did all they could to minimise civilian casualties.
The spokesman said he did know of two slightly injured civilians who had been treated at the British base.
Afghan human rights and government officials say more than 70 civilians have been killed by foreign forces in the last three months, mostly by the US-led coalition working outside Nato's mandate.
Meanwhile, the Nato-led force says one of its members died in combat operations on Friday in eastern Afghanistan.
Afghan officials say at least 25 guerrillas, one policeman and four civilians have died in further violence around the country, including 20 Taleban fighters reportedly killed in a battle with Nato and Afghan troops in the southern province of Kandahar.