American troops have intervened, for the first time, in a clash between government forces and a group of gunmen in Afghanistan.

The clashes started when the Kuchis ignored an ultimatum to leave government owned land

Khayal Baaz, Local military commander

A local Afghan official said that American helicopters broke up a gun battle between a group of armed men and local government forces over a land dispute.

The official said that after the two sides had exchanged fire with light machine-guns and rocket-propelled grenades for two hours, the American helicopters attacked the gunmen's positions on cliffs surrounding Kikara village, about a kilometre south-east of the city of Khost.

Six gunmen were reported to be wounded in the clash.

Correspondents say it is not clear whether the American forces intervened at the request of the local authorities, or had acted independently.

Strengthening grip

"The clashes started when the Kuchis (local tribe) ignored an ultimatum (by the local government) to leave government-owned land," Kahayal Baaz, a local military commander, told the BBC Pashto service.

Reports say the Kuchis began to fire on government soldiers, who had gone there after the ultimatum was issued, and wounded two soldiers.

US forces are hunting Taleban and al-Qaeda fighters

Nearly 8,000 US soldiers have been stationed in Afghanistan to hunt members of the ousted Taleban regime and al-Qaeda network of Osama Bin Laden.

Bin Laden is accused by Washington of masterminding the 11 September attacks on New York and Washington last year.

US special forces have several forward bases in the Khost province, where they have been involved in search operations and occasional clashes with suspected Taleban and al- Qaeda sympathisers.

The incident came as Afghan President Hamid Karzai sought to strengthen his grip on outlying regions, where warlords still wield much influence.