Updated

U.S. soldiers returning from the front lines in eastern Afghanistan on Saturday described dangerous cave-by-cave searches for the few remaining Al Qaeda and Taliban fighters holed up in the rugged hills of the Shah-e-Kot valley.

The new accounts came after U.S. and Canadian troops found a cache of mortars, grenades and rockets as they scoured the mountains Friday.

Loud explosions could be heard echoing off the snow-covered peaks as the captured weapons were blown up, according to the Canadian Press news agency, which has a reporter with the Canadian force.

The most intense combat in Operation Anaconda ended more than a week ago. But about 500 Canadian and U.S. infantrymen, along with special forces and U.S.-allied Afghan fighters, have been searching the cave complexes for the past several days.

Coalition soldiers shot and killed an enemy fighter who was apparently trying to bury a fallen comrade, said Staff Sgt. Del Rodriguez, 31, of the 10th Mountain Division.

"We plugged him," said Rodriguez, of Redding, Calif., of the incident on Thursday. The unit continued on through the rocks and up the hills before spotting the body of another fighter that appeared to have died earlier, he said.

"I wasn't going to take any chances so we shot him too," said Staff Sgt. Lonnie Schultz, 28, of Denver, Colo. Rodriguez said it appeared that the first fighter had been trying to bury the other man.

Rodriguez and the others found "spider holes" in the rocks that enemy fighters could pop out of, and which led to an underground chamber. Inside the bunker were rocket propelled grenade rounds and other ammunition, as well as medical supplies, including IVs hanging from the cave ceiling.

"We didn't expect to see anything like that," said Sgt. Jonathan Wightman, 26, Phoenix, Ariz., who also took part in the assault. "It's the best damn bunker I've ever seen."

Rodriguez said that later that night, four Afghan fighters were spotted by an AC-130 Spectre in the same area, moving toward the valley floor. U.S. allied Afghan fighters tracked them to the valley and killed them in a firefight, Rodriguez said.

At the Pentagon, Defense Secretary Donald Rumsfeld said Friday the fighting is "winding down," but skirmishes continue.

He said a key objective of the U.S.-led campaign is to keep Al Qaeda and Taliban fighters from regrouping, either in Afghanistan or in neighboring countries.

"We need to make sure that the well-trained terrorists who left Afghanistan do not set up sanctuaries in other nations," Rumsfeld said.

A U.S. official said that numerous Al Qaeda fighters fleeing battles near Shah-e-Kot are believed to have escaped into Pakistan.

It is unclear how many of the terrorist group's fighters fleeing the U.S.-led crackdown evaded Pakistani troops to cross the border, said the official said, speaking on condition of anonymity

Rumsfeld said he saw little chance of expanding the international security force now keeping order in Afghanistan's capital. At a Pentagon news conference, he said it was likely that the current force of 4,500 foreign troops, led by Britain, would remain in Kabul until year's end.

Interim Prime Minister Hamid Karzai repeatedly has called for a larger peacekeeping force that would deploy outside Kabul, and humanitarian groups have said there is an urgent need to improve security.

It is still uncertain how many enemy fighters have been killed. Some U.S. officers have estimated as many as 500 Al Qaeda fighters were killed, but Afghan fighters said only a couple dozen bodies had been found. Others may be buried in caves that collapsed during bombing.

"There are clearly a lot of people who are willing to guess at those numbers," Rumsfeld said. "I'm not one of them."

The coalition death toll stood at eight U.S. special forces troops and three Afghan allied fighters.