US-led coalition forces killed 15 militants in an operation in eastern Afghanistan overnight, the U.S. military said on Saturday, but a provincial governor said at least 10 civilians were killed in the raid.

The issue of civilian casualties is sensitive in Afghanistan and has eroded public support for international troops in the country. It also has driven a wedge between President Hamid Karzai and his Western backers.

"There was a ground operation targeting a Taliban commander. A number of militants maneuvered on the force with small arms fire," U.S. military spokesman Colonel Greg Julian said.

Eleven militants were killed by small arms fire while four were killed by close air support, the U.S. military said in a statement.

"In an area where there was no threat to civilians, precision air weapons, not bombs, were used," Julian said.

But the governor of eastern Laghman province, where the incident took place, said initial reports showed that 10 civilians were killed during the U.S.-led operation.

"We have sent a team to the area to investigate, but the preliminary reports show that 10 civilians were killed as well as three who might be Taliban," Provincial Governor Lutfullah Mashal told Reuters.

Mashal said the operation, in Mehtar Lam district, some 60 km (40 miles) east of Kabul, had not been coordinated with local officials.

"The local administration, the police, the ANA (Afghan National Army) and NDS (National Directorate of Security) were not made aware of this incident," Mashal said. "Nobody was informed and it was not coordinated with us at all."

Earlier, a provincial Afghan official and a village elder told Reuters up to 22 civilians had been killed during the raid, an assertion denied by the U.S. military, which said it had no reports of civilian deaths "at this point."

"Their bodies are on the ground. If you (Afghan government) do not believe us, you have helicopters and you should come to the area and see that these are civilians," Malik Rahman Gul, a village elder, who said 21 civilians were killed, told Reuters.

The U.S. military said it would investigate any claims of civilian casualties.

Protests

Up to a hundred protesters gathered in the provincial capital to demonstrate against the alleged civilian killings, a Reuters witness said.

During the operation, soldiers searched several compounds and identified one of the killed militants as a woman, the U.S. military said, adding that she had been carrying a rocket-propelled grenade.-Reuters