Taliban fighters have attacked and burned 24 trucks carrying fuel and supplies to US troops in southern Afghanistan.

A Taliban spokesman claimed responsibility for the attack on the Nato convoy destined for southern Helmand province, and said the assault prompted US forces to evacuate the Singin military base.

"Twenty-four fuel and supply trucks on their way to Qalat Mousa in the southern province of Helmand have been burnt," spokesman Qari Yousuf Ahmadi said.

"Our fighters have forced the US forces to leave their bases. Seventy per cent of the province's organisations have stopped their activities," he said.

Nato denial

Nato denied the Taliban’s claims and said that its troops had killed 40 Taliban fighters in offensives this week in eastern Afghanistan, Nato's International Security Assistance Force (Isaf) forces said on Tuesday.

"The joint force has killed approximately 40 Taliban fighters and captured eight key Taliban facilitators in recent days."

One Nato soldier was killed on Tuesday in fighting in southern Afghanistan, the alliance said, taking to 12 the number of Western troops killed in Taliban attacks in the past three days.

The latest death brings to 457 the toll of international soldiers killed in the Afghan war so far this year, compared with 520 for the whole last year.

Twelve international soldiers have been killed since Saturday, according to an AFP tally based on that kept by the casualties.org website, seven of them Americans.

The deteriorating security situation in Afghanistan has sparked concerns ahead of the country's parliamentary elections, due to take place on September 18.