The Nato said at least two Afghan soldiers died along with the eight Americans. Afghan provincial authorities said they had lost contact with scores of Afghan policemen after the day-long attack and did not know whether they were dead or alive.

The fighting took place in Nuristan province’s Kamdesh district in high mountains along the eastern border with Pakistan on Saturday but was not reported until Sunday.

The battle showed the ferocity of the insurgency in a part of the country that the US forces have decided to abandon after years of heavy fighting. The troops had already announced plans to withdraw from the area as part of commander General Stanley McChrystal’s strategy to focus his forces on population centres.

Militia from a local mosque and a nearby village launched the attacks on two joint Nato  and Afghan outposts, the Nato-led International Security Assistance Force said.

A Taliban spokesman, Zabihullah Mujahid, said the movement was behind the attack.