Afghan and US troops have joined forces against regrouping Taleban

The ambush took place in the vicinity of Gereshk at 1130 GMT on Saturday while the soldiers were on a reconnaissance mission, the US military said.

Gereshk is just over 100 kilometres (62 miles) from Kandahar, a key Taleban stronghold until they were defeated by a US-led military operation following the 11 September attacks.

A large operation began on Saturday in the area to hunt down remnant Taleban fighters.

Joint operation

US soldiers are fighting alongside around 1,000 Afghan soldiers to flush out a group of Taleban fighters, believed to number about 100.

The governor of Uruzgan province said four Taleban suspects have been killed so far and six arrested.

A police spokesman in Kandahar said American bombers have pounded the city.

Taleban members have been reportedly living in the area for some time.

They are accused of shooting a Red Cross worker in Uruzgan on Thursday.

The Red Cross convoy was stopped by a group of armed men who shot the only expatriate among them.

In recent months there have been reports that the Taleban is regrouping, or at least becoming more active.

A senior Taleban commander has told the BBC the Taleban hopes to regain power in Afghanistan.