Kabul  - Hundreds of villagers gathered at the center of a town in eastern Afghanistan protesting the alleged killing of two civilians in a US military raid, officials said Monday.

A father and his four-year-old son were killed when their house came under rocket fire from a US military helicopter in Khogyani district, eastern Nangarhar province, on Sunday night, Haji Zelmai, the district's administrative chief, said.

He said US forces were conducting an operation against a militant group when they mistakenly hit the villager's house.

The protesters were chanting anti-US slogans and asked the central government to punish the soldiers, said Abdul Raouf Khan, a villager who participated in the demonstration.

"We want the foreign forces to apologize for their action and ask the government to assure us that this kind of action will never happen again," Khan said.

Meanwhile, coalition spokesman Nathan Perry confirmed the incident. A military helicopter had been called in to support troops under attack by militants.

The troops had spotted four people planting roadside bombs in the area, he said.

One militant was killed and a cache of roadside bomb-making materials was found and destroyed, Perry said, but denied the casualty reports.

"There is no report of civilian casualties," Perry said.

Protesters were assured by the Afghan authorities that their complaints would be taken to the relevant provincial authorities, Zelmai said.

Civilian deaths during the US-led military operations against the Taliban have become a serious concern for the government of western-backed President Hamid Karzai.

Karzai urged the coalition forces, that have some 70,000 troops in the country, to take all measures necessary to avert civilian casualties, warning them that mounting civilian deaths would increase support for the Taliban. (dpa)