U.S. and Canadian troops worked to finish what Operation Anaconda started Friday, trailing four Al Qaeda fighters through the mountainous terrain of eastern Afghanistan after the enemy escaped following a gunbattle.

The search, involving helicopters, commandos and ground troops, came after coalition forces subdued a cell of suspected Al Qaeda or Taliban fighters with anti-tank weapons, grenades, heavy machine guns and small arms fire. There were no coalition casualties, according to the Canadian Press news agency, which has a reporter with the Canadian troops.

"Today is March 15, so here's a sooth for the Al Qaeda," said Maj. Bryan Hilferty, a spokesman for the 10th Mountain Division. "If you come out of your holes, I'd say beware the Ides of March."

Coalition troops clearing caves and bunkers in the Shah-e-Kot valley also killed three enemy fighters after a separate 90-minute gunbattle.

The coalition casualty toll stood at eight U.S. special forces troops and three Afghan allied fighters, all killed in the first two days of the operation.

U.S., Canadian and Afghan troops scoured the area around the Shah-e-Kot valley for intelligence information and any stray enemy fighters after Al Qaeda and its Afghan Taliban allies fled the area following 12 days of airstrikes and ground fighting in the biggest U.S.-led offensive of the Afghan war.

Maj. Gen. Frank L. Hagenbeck, the commander of all coalition troops in Afghanistan, told reporters he had called for DNA tests on remains of Al Qaeda fighters to determine whether any of them were senior figures in the terrorist network.

Neither Usama bin Laden nor Taliban leader Mullah Mohammed Omar was believed to be in the area on March 2, when Operation Anaconda was launched.

Hagenbeck said some of the 20 prisoners captured indicated that "second and third tier" Al Qaeda leaders had been slain.

"Even if it's a long shot that maybe one of these Al Qaeda leaders (was there), we want to go through every means we've got available to us to try to positively identify them," Hagenbeck said.

Hagenbeck has said bomb-making devices, extensive weapons caches, and manuals on how to attack cars and bridges have already been found by coalition forces searching the caves. He said some of the weapons will be turned over to the Afghan army.

Hagenbeck acknowledged that some civilians were killed in the fighting, though he did not say how many. He blamed the deaths on the Al Qaeda fighters, who set up mortar positions between the houses in the hamlets of the Shah-e-Kot Valley.

It is still uncertain how many enemy fighters were killed in the operation. Some U.S. officer have estimated as many as 500 Al Qaeda fighters were killed, but Afghan fighters said only 25 bodies had been found in the initial sweep of the area. Others may be buried in caves that collapsed during the bombing.

U.S. and Afghan officials are also uncertain how many fighters may have escaped and are trying to flee to Pakistan. U.S. attack helicopters patrolled over the area Thursday trying to locate any pockets of Al Qaeda survivors.

Pentagon spokeswoman Victoria Clarke said Wednesday that fighting in the Shah-e-Kot area had "mostly ended" and that troops were in the "exploitation phase," going cave to cave in search of bodies, weapons and intelligence information.

"We will have a long way to go in Afghanistan," she warned. U.S. and Afghan officials believe there are still pockets of Al Qaeda and Taliban fugitives in several southern and central provinces, as well as in Pakistan.

The Associated Press contributed to this report.