The British forces, however, could not confirm the rebel toll but said "possibly a significant number" were killed in the fighting in the Kajaki district of the southern province of Helmand that started Saturday.

"In the two-day operation 30 Taliban were killed and another 20 were wounded," Helmand police chief Mohammad Nabi Mullahkhail told AFP. He said the operation concluded Sunday.

"Some of the insurgents' bodies are still left at the battle site," he said.

Lieutenant Colonel Rory Bruce of the British task force in Helmand said there were no other casualties to the troops beside the death, the first this year among the roughly 40,000 foreign soldiers in Afghanistan.

"A number of Taliban were killed in the course of the action, but we don't know how many ... possibly a significant number," he told AFP.

A purported Taliban spokesman, Mohammad Yousuf Ahmadi, said only three fighters were killed and eight wounded.

The hardliners routinely understate their own casualties while exaggerating those of the Afghan or foreign militaries, the main targets in an insurgency launched after the Taliban were forced out of government in 2001.

Death tolls in clashes between security forces and rebels in Afghanistan's dragging insurgency are usually impossible to verify, with various sides giving different accounts including over whether civilians are killed.

Around 4,000 British troops are based in Helmand, one of the most volatile provinces in Afghanistan and where some areas fall outside of government control.

Helmand produces most of the country's opium crop -- which makes up 90 percent of the world supply -- and the narco-trade is said to feed the insurgency, which was its deadliest last year.