GARDEZ, March 7: Snow swept over mountain fighting between US-led forces and Taliban-Al Qaeda guerillas on Thursday, adding an unpredictable twist to the largest US-led battle in Afghanistan so far.

American forces back from the high-altitude frontline in eastern Afghanistan reported sharp temperature drops, while Afghan soldiers worried they would lose crucial US bombing support as bad weather closed in.

The American soldiers, who cannot be named, said temperatures had dropped by at least 10 degrees centigrade during the course of Thursday.

Before snow and high winds hit the Gardez area, 150kms south of Kabul, on Thursday, B-52 bombers had pounded guerilla positions after a day in which, according to the US military, about 100 opposition fighters were killed in battle.

US military spokesman Major Brian Hilferty said that around 1,000 Taliban and Al Qaeda fighters had taken part in nearly a week of fighting, defending caves and bunkers in the snow-covered mountains, but estimated around half of that number were dead.

He said there could have been some civilians killed during the heavy bombing and fighting, with some of the Taliban and Al Qaeda men thought to be holed up in caves with their families.

“In fighting on Wednesday we estimate we killed 100 Taliban (and Al Qaeda),” Hilferty said at a news conference.

“We might have killed non-combatants,” he said in response to a question. “But they certainly went in there knowing what they were going into. We have no indication, we haven’t seen little kids in a yard and we’ve blown it up, or women walking around and then shot.”

With around 2,000 Allied and US-backed Afghan troops now on the ground in the mountains their resupply was crucial, Hilferty said at Bagram Air Base, on the outskirts of Kabul.

“We are sending in by helicopter fuel, food, ammunition and other equipment,” he said.

US military officials said they knew bad weather was approaching which added urgency to supply flights into the barren windswept area.

Commander Abdul Muteen, who has about 135 fighters in the Afghan force of about 800, said before the bad weather arrived possible rebel reinforcement routes had been sealed and fighters were beginning to enter tunnel systems held by the diehard Taliban and Al Qaeda fighters.

But he feared the besieged guerillas might now try to slip away under cover of snow.

“The weather may ground some US planes and these Taliban know the area very well and might try to slip through our lines and escape,” he told Reuters.

The US military has ordered up to 300 extra troops, 17 attack helicopters and several A-10 ground-attack aircraft armed with rapid-fire cannon to the battlefield to counter the rebels.

CASUALTIES: The battle twists along a 10-km front line of bunkers and caves up to the top of 3,000 metres peaks around the village of Shahi Kot.