Mesa Verde National Park, Colo. A wildfire that had already burned 3,500 acres made a 3-mile run overnight, spreading into nearby land on the Ute Mountain Ute reservation.
A second wildfire broke out about 40 miles to the northwest Saturday afternoon, forcing some evacuations and diverting planes and firefighters from the Mesa Verde fire.
"We're running short on resources," said Deb Koening, spokeswoman at an interagency fire dispatch center in Durango.
Mesa Verde remained closed indefinitely as more than 500 firefighters struggled to reach flames moving aggressively in canyons inside the park.
About 1,000 tourists were evacuated Thursday after the fire started, apparently from a lightning strike.
Officials were still working to map the size of the fire Saturday. It was 5 percent contained Friday night.
"When they get this big, you don't put them out," said fire management officer Tim Oliverious of the U.S. Park Service. "It will take a major change in the weather, topography or fuels, and right now the forces are lined up in favor of the fire."
None of the park's well-known ancient Indian ruins, cliff dwellings or other attractions were damaged, and buried archaeological sites in the area of the fire were expected to survive, Oliverious said.
The fire was burning on the rugged eastern boundary of the park, about 260 miles southwest of Denver. It moved south into remote Ute reservation land, said Justin Dombrowski, a spokesman for the fire management team.
No serious injuries were reported.
The new fire had burned 80 acres by Saturday evening and forced the evacuation of 10 homes northwest of Mesa Verde, near the Hovenweep National Monument, said Lt. Kalvin Boggs of the Montezuma County Sheriff's office.
Firefighters were battling two other large fires in northwestern Colorado, both caused by lightning.
The largest was burning on 1,500 acres about seven miles east of Rangely and threatened two trailers and two cabins. It was 10 percent contained Saturday.
Nearly 56,000 fires have burned 2.8 million acres nationwide this season, according to the National Interagency Fire Center in Idaho, the worst acreage total since 1996.
- On the Net: Fire center: www.nifc.gov. Mesa Verde National Park: www.nps.gov/meve/.