An air strike by foreign forces killed 20 to 30 villagers, including women and children, in southern Afghanistan overnight, a governor and a witness told AFP Wednesday.
The new claim of civilians dying in operations against Taliban fighters comes after nearly 60 people were said to have been killed in such incidents late last month, prompting angry demonstrations.
War planes bombed a village in the Sangin district of Helmand province late Tuesday, provincial governor Assadullah Wafa said.
"Twenty-one civilians including women and children were killed," he said.
A man from the bombed village of Sarwan Qala told AFP the toll was higher, at about 30 dead. It was not clear whose planes were involved.
NATO's International Security Assistance Force said it was "unaware at this time of any NATO air strikes resulting in civilian casualties over the past 24 hours."
The separate US-led coalition said it was involved in an "engagement" in the same area of Sangin but made no mention of air strikes.
A coalition soldier was killed in the incident, when an Afghan and coalition convoy was attacked by Taliban fighters, it said.
Villager Noorullah said the war planes started bombing not long before midnight.
"Around 30 people are dead," he said by telephone. "The number might rise because there are still people under the debris."
He said most of the dead and wounded were women and children. "We took the wounded kids to the foreign forces base to show them who they have bombed."
Mounting civilian casualties are fuelling Afghan resentment about the presence of international forces and undermining the government.
President Hamid Karzai last week summoned the foreign commanders and top diplomats to tell them to take more care.
UN and Afghan investigations found about 50 civilians were killed in operations by the US-led coalition and US Special Forces in the western province of Herat on the weekend of April 27.
The coalition initially denied there had been civilian casualties, saying 136 Taliban fighters had been killed.
Separately, residents in the eastern province of Nangarhar accused the coalition in a series of demonstrations last week of killing six civilians in late April, including two women.
The incident was not far from an area where US Marines opened fire on civilians in March after a suicide bombing. A US commander said in Washington Tuesday that 19 people were killed and 50 injured in this incident.
The commander, Colonel John Nicholson, told reporters he was "deeply, deeply ashamed and terribly sorry that Americans have killed and wounded innocent Afghan people."
ISAF commanders are looking into ways to ensure "closer engagement" of the government in operations, NATO spokesman Nicholas Lunt said Wednesday.
The force knew its "ability to operate here in support of the government of Afghanistan is dependent on the support of the people of Afghanistan," he said.
"We know very well that civilian deaths and injuries undermine this goodwill and support."
