SIRKANKEL (Afghanistan), March 6: US-led troops backed by punishing round-the-clock air bombardment pushed on Wednesday for control of one of the last Al Qaeda strongholds in Afghanistan in a fifth day of fierce fighting.

Some 400 Al Qaeda and Taliban fighters have been killed since the largest air- and ground offensive of the war was launched on Saturday, a US military spokesman said.

Eight US servicemen have been killed and some 50 wounded in intense fighting in the Arma mountains of Paktia province, in eastern Afghanistan, US Major Brian Hilferty said.

Hilferty, speaking to reporters on Wednesday at Bagram air base, near Kabul, said he did not know how many Al Qaeda guerillas and supporters of the Taliban were left.

At the start of the offensive the Pentagon gave a figure of “hundreds” of hostile fighters regrouping in the rugged mountains bordering Pakistan, but local Afghan commanders put the number as high as 2,300.

Some 2,000 allied troops, including around 950 US regular and special forces soldiers, are taking part in “Operation Anaconda”, named after the snake that encircles and crushes its prey.

Some 200 commandos from Australia, Canada, Denmark, France, Germany and Norway are also on the ground, backed by several hundred Afghans under the command of local Afghan warlord Zia Lodin.

Fighting was continuing on Wednesday in the Shahi Kot valley, some 50kms south of the provincial capital Gardez, Hilferty said, and US planes continued a relentless bombardment of fighters holed up in cave complexes.

US commanders had expected the Al Qaeda and Taliban fighters to either flee or surrender.

But the guerillas, believed to be mostly Chechens, Pakistanis and Uzbeks, fought a pitched battle with Afghan troops for control of Sirkankel, a town about 40 kilometres from Gardez, and ambushed US forces with mortar fire as they landed in the mountains to the south and east.

Three Afghan allies were killed on Saturday as the coalition forces met heavy fire from Al Qaeda fighters, Hilferty said. A US special forces soldier with the Afghan troops was also killed when his vehicle was hit.

“I didn’t really expect them to try and duke it out with us,” said Lieutenant Colonel Ron Corkran, commander of a US infantry battalion. “I was just surprised at the intensity of what I saw on the valley floor.”

A mortar ambush on Saturday injured at least 12 soldiers from the US 10th Mountain Division as they landed right on top of an Al Qaeda command bunker near the village of Marzak, south of here.

“I’ve never been so scared in my life,” said Sergeant First Class Thomas Abbott, whose right arm was injured by shrapnel. “We thought we were all going to die.”

Troops from the US 101st Airborne Division moved into the mountains north and east of Sirkankel to block any Al Qaeda escape, while Australian and US special forces troops blocked escape routes to the south.

Bolstered by fresh reinforcements, US troops regrouped and launched an assault south along the high ground east of the valley, searching the snow-covered mountains for caves and other signs of Al Qaeda fighters.

Six special forces soldiers died on Sunday in an ambush as they tried to rescue a captured comrade, in an action which also saw two US helicopters damaged.

The captured serviceman — a 32-year-old member of the elite US Navy SEALs who had fallen out of a helicopter — was later found to have been executed by his captors.—AFP