LOS ALAMOS, N.M. (Reuters) - An army of 1,000 firefighters on the ground and in the  sky struggled on Saturday to contain a wind-driven forest fire that forced thousands of  people from their homes, caused $1 billion in damages and charred vast areas at the Los  Alamos National Laboratory, the top U.S. nuclear research facility.

 Despite their efforts, the mighty blaze spread like a fast-growing cancer across more than  36,000 acres of scenic northern New Mexico, sending up huge plumes of smoke that were  visible for hundreds of miles.

 Officials had expected cooler temperatures and calmer winds to help them get a grip on the  fire, which was deliberately set last week as part of a forest management program to avert  just such disasters.

                         But on Saturday afternoon officials said winds had kicked up                          again and left them scrambling to hold on to the 5 percent of                          the fire they had contained on Friday night.

                         ``This thing is growing and we don't where it's going to end                          up,'' U.S. Forest Service fire information officer Jim Paxon  said during a news conference on Saturday. ``It will be a long time before we get this fire  contained ... this fire is going to burn for weeks.''

 Paxon said the fire, which had so far destroyed 261 homes and caused an estimated $1  billion in damage, was spreading in three directions all around the Los Alamos laboratory  and was near a town and two Indian reservations.

 ``We just simply don't have enough people power and machines and aircraft to just stop it  right now,'' he said.

 Officials said more than 1,000 firefighters using hand tools, heavy equipment and fire hoses  were battling the flames, aided by a fleet of 18 firefighting airplanes and helicopters dumping  water and fire retardants.

 Along with the winds, Paxon said the fire was being fueled by the effects of a prolonged  drought that was the most severe in New Mexico's recorded history, dating back to the  1700s.

 President Clinton on Saturday declared a 12-county region of New Mexico a disaster area,  freeing up federal aid to help those affected by the wildfire.

 Area Around The Lab Burned

 The blaze began as a controlled burn last week by the Forest Service to clear underbrush  and manage the forest to limit the possibility of big fires.

 But wind gusts of up to 60 miles an hour caused the fire to race out of control, through the  ponderosa pine forests at the national laboratory 40 miles northwest of Santa Fe.

 Officials said 30 percent of the 43 square mile land area of the Los Alamos laboratory,  where scientists built the first U.S. atomic bomb during the Second World War, had been  burned. None of the lab's permanent buildings were damaged.

 The laboratory has been closed because of the fire, but a few administrative functions could  reopen as early as Monday, lab director John Browne said.

 Air monitors had detected no radioactive releases, but lab officials said they were still taking  care to protect a warehouse containing low-level nuclear waste stored above ground. Other,  more potent nuclear materials, are stored in well-protected underground bunkers, they said.

 Officials took reporters to the critical storage areas on Saturday, where the fire had  advanced to the surrounding fences before firefighter working through the night on Friday  subdued the flames with foam.

 The charred ground was still smoking and small fires could be seen in the distance.

 Fresh Fire Begins

 Since the United States stopped nuclear testing in the 1990s, the facility's main charge is to  ensure that the nuclear weapons stockpile stays in working order.

 U.S Interior Secretary Bruce Babbitt on Friday declared a 30-day moratorium on controlled  burns west of the Rocky Mountains, but that was small comfort for the 20,000 people  evacuated from their homes at the approach of the fire.

 They were being housed in refugee centers, hotels and private homes in the Santa Fe area.  Officials said some of the evacuees would be driven by their property on Sunday, but that it  would be perhaps a week before they could return home.

 Roy Weaver, superintendent of the nearby Bandelier National Monument, who ordered the  controlled burn, was suspended on Thursday pending a federal investigation. He said the  burn was carefully planned but that he had not seen a fax from the National Weather Service  predicting high winds in the area.

 At the same time that the fire was burning at Los Alamos, firefighters near the mountain town  of Cloudcroft, New Mexico, 200 miles to the south, were wrestling with a 20,000 acre  forest fire that forced the evacuation of more than 100 people and threatened dozens of  homes. They said the fire, caused by a fallen power line, was 50 percent contained.