Battle rages in Afghan mountains

The mountains are proving a tough nut to crack

US forces and their Afghan allies have been engaged for a second day in heavy fighting against Taleban and al-Qaeda forces in the mountains of eastern Afghanistan.

Hand over Taleban and al-Qaeda or you will be destroyed

US propaganda leaflet

US military spokesman Colonel Rick Thomas spoke of "pretty intense fire fights".

The US estimates there are several hundred militants resisting what is reportedly the biggest US-led ground offensive of the war.

1,500 Afghan fighters are moving against the Taleban stronghold

A US soldier and three pro-US Afghan troops have been killed while the militants are said to have suffered heavy casualties.

The second day of the operation against the Taleban and al-Qaeda stronghold began with air strikes by B-52 bombers.

Strong explosions could be heard in the Shah-e-Kot mountains, 30km (20 miles) south of Gardez in Paktia province, which has been hit by 80 bombs in recent days.

Bombing was also reported on the Kharwar mountain range in the neighbouring Logar province, where pro-US Afghan forces were said to be battling Taleban and al-Qaeda fighters.

'Several hundred militants'

US aircraft have also dropped thousands of leaflets over Paktia province, urging local people to surrender al-Qaeda and Taleban suspects or "be destroyed". The leaflets were printed in Dari and Pashto, the two main languages of Afghanistan.

Warning: "Surrender militants or die"

A picture on the leaflet showed a truck packed with heavily-armed Taleban fighters.

The military offensive has run into strong resistance with Afghan and US driven back by heavy fire on Saturday.

Advancing troops encountered artillery, mortar and heavy machine gun fire.

An Afghan doctor in Gardez said six Americans had been wounded in addition to the one fatality.

According to an Afghan soldier injured in the assault, the American who died was killed when a mortar shell hit the vehicle he was riding in.

About 30 US soldiers are said to be involved with about 1,500 Afghan troops.

The militants were initially thought to number between 3,000 and 5,000, but US spokesman Major Ralph Mills put the figure at "several hundred" on Sunday.

US sources told Reuters that militants had been buying hundreds of sacks of food in local markets every week.

New weapons

The US said two "thermobaric" bombs had been dropped on the mountains.

Click here for a guide to US military options

The 2,000-pound (907-kg) laser-guided weapons are filled with a special explosive mixture that creates a high-pressure blast, driving all of the air out of a cave and potentially choking those inside.

They were tested by the US in December and officials said in January that they would be rushed to Afghanistan for the campaign to root out supporters of Saudi-born dissident Osama Bin Laden.

Russia has prompted international protests by using similar fuel-air bombs in the republic of Chechnya.

The mountains around Gardez have been a hiding place for Afghan warriors since anti-Soviet guerrillas used them as a base for their fight against Soviet troops in the 1980s.