An air raid by foreign forces has killed 21 civilians in Afghanistan's southern province of Helmand, the provincial governor has said.

Assadullah Wafa said a village in Sangin district of Helmand province was bombed late on Tuesday.

"Twenty-one civilians, including women and children, were killed," the governor said.

It was not clear whether the raid was by Nato's International Security Assistance Force or the separate US-led coalition, which both operate alongside the Afghan military.

Nato denial

James Bays, Al Jazeera's correspondent in Afghanistan, said Taliban sources were putting the number killed at about 50, while local sources said it was at least 40.

Bays said Nato had denied any knowledge of the air raid. The US-led coalition said it was checking the report.

He said there had been intense fighting in Sangin in recent days.

The claim of civilian casualties is the latest in a string of such incidents which have angered Afghans and prompted Hamid Karzai, the Afghan president, to tell the foreign forces in his country to take more care in battle situations.

Authorities are still investigating an incident in the western province of Herat last month where UN and provincial Afghan investigations have found that about 50 civilians were killed.

'Shameful'

The latest casualties came even as a US commander admitted that civilian deaths in the country were "shameful".

Colonel John Nicholson, a US brigade commander, apologised on Tuesday to family members of 19 Afghans killed and 50 injured by US forces in an incident more than two months ago.

"I stand before you today deeply, deeply ashamed and terribly sorry that Americans have killed and wounded innocent Afghan  people," Nicholson said he told the family members.

"This was a terrible, terrible mistake, and my nation grieves with you for your loss and suffering. We humbly ask for your respect and forgiveness," he said.

There has been growing anger in Afghanistan over civilian deaths in coalition military operations.

PHOTO CAPTION

Villagers surrounded the bodies of Afghan men who were allegedly killed during a raid in Bati Kot area of Nangarhar province, east of Kabul, Afghanistan on Sunday, April 29, 2007. (AP)

Al-Jazeera