WASHINGTON, Feb. 10 — High in the mountains of southeastern Afghanistan, troops of the 101st Airborne Division spent today at the grisly task of gathering evidence at the campsite where a missile-carrying American Predator drone fired at a small band of suspected members of Al Qaeda a week ago, military officials said.

They picked up communications gear, weapons, documents and the remains of people killed in the strike, any of which might help determine who those people were.

Wintry weather and the complications of a high-altitude helicopter mission hampered efforts to determine the impact of the missile strike last Monday, which was carried out by a Predator armed with Hellfire antitank missiles and operated by remote control by the Central Intelligence Agency.

Military and intelligence officials said the drone had loitered over the Zawar Kili area, in Paktia Province, for several hours and had spotted a group of men near a truck at a camp believed to have been used by Al Qaeda, Osama bin Laden's network.

A detachment of 50 to 100 troops landed at the site on Friday. Senior military officers explained that the large number indicated the unstable politics of the area and that it was important to have a sizable security force accompany the intelligence and forensics mission.

"Some of the evidence that has been collected has been human remains," Cmdr. Dan Keesee of the Navy, a spokesman at the United States Central Command, said today. He said they had collected some small weapons and some documents.

He said that the troops would remain at the site, at least overnight, and that the search was to resume again at first light on Monday.

Intelligence officials who reviewed reports from the Predator strike said at least one person was killed. Statements by American officials that a tall bearded man was seen through the Predator's camera caused debate over whether Mr. bin Laden had been caught in the attack. But Pentagon, military and Congressional officials said there was no evidence that he was there.

"We don't know where bin Laden is," said Senator Bob Graham, chairman of the Senate Select Committee on Intelligence. Speaking this morning on the NBC News program "Meet the Press," Mr. Graham, Democrat of Florida, said, "The best intelligence is he is still alive, but where he is continues to be a question mark."

Afghan commanders said late last week that it was even possible that the men who came under fire at Zawar Kili were not terrorist leaders, but local smugglers scouring a known Qaeda camp for abandoned weapons.

The fragmentary human remains could be of use in identifying remains as Mr. bin Laden's, if the DNA matched genetic patterns in his extended family, officials said.

Senior military officials said collecting and analyzing evidence from the site could take weeks.

The war in Afghanistan is the first in which armed Predator drones have been used in combat. In recent conflicts such as in Bosnia and Kosovo, American forces used unmanned aircraft for surveillance.

But even before Sept. 11, American military and intelligence officials were frustrated by the elusiveness of terrorist leaders they had been tracking in Afghanistan in the last few years.

After the August 1998 bombings of two American embassies in East Africa, the United States launched a long-range cruise missile strike on sites in Afghanistan it believed to be terrorist training camps, but failed to kill either Mr. bin Laden or other senior Al Qaeda leaders — even though it is believed they had been at the complex just a few hours before.

One source of frustration for the United States was that on the rare occasions when Al Qaeda leaders were sighted by American surveillance aircraft, the leaders would move on long before a bombing raid could be launched against them.

The idea of arming the Predator seemed to provide the answer: Mr. bin Laden and his lieutenants could be attacked by the same surveillance drone that spotted them.

During testimony before the House Armed Services Committee last week, Defense Secretary Donald H. Rumsfeld said the Pentagon had been won over by the armed Predator's performance.

"If you have an unarmed Predator that's out there gathering intelligence information and you replace it with an armed Predator, that not only can gather intelligence information, but then can actually fire a Hellfire or, even better, an upgraded Hellfire with a better warhead that will do a better job, you've got different lethality," he said.

But the Predator program has not been without problems. An internal Pentagon report completed last year said tests conducted in 2000 found the Predator performed well only in daylight and in clear weather. It broke down too often, could not always stay over targets as long as desired and often lost communication links in rain, the report said.

Since the United States military campaign in Afghanistan began in October, the C.I.A.'s armed Predators have fired missiles at targets there dozens of times, American officials said. A Predator operated by the intelligence agency played a crucial role in one significant attack, in which Muhammad Atef, the Qaeda military chief, was believed to have been killed, officials said.

During that November raid, an armed Predator identified the target. A Navy F/A-18 was then called in to bomb the target. The Predator then launched its missiles at people fleeing the site after the initial bombing, officials said.

For large, fixed targets, the military still prefers bombers or attack jets, while the Predator is useful primarily for quickly striking at small, mobile targets and people, like the targets last Monday. Decisions on when to use the C.I.A.-operated Predators in attacks are coordinated between the United States military — in this case Central Command — and the C.I.A., officials said.

The Predator's success in Afghanistan is already having an effect on the C.I.A.'s budget. Although the financing figure is classified, the Bush administration's 2003 spending proposal is said to provide more money for drone aircraft for the C.I.A. And the Pentagon's proposed budget for 2003 would spend $1 billion to develop or speed up production of unpiloted aircraft, including the Predator and the more advanced Global Hawk.