Rescuers in the Philippines all but gave up hope Monday of finding survivors in mudslide-swamped villages on the slopes of the Mayon volcano, five days after a typhoon killed an estimated 1,000 people.

Official figures showed 450 dead, 507 injured and 599 missing, but Sen. Richard Gordon, head of the local Red Cross, said he believed more than 1,000 died in the thousands of homes buried under volcanic debris, mud and flood waters.

Juan Garcia, mayor of devastated Guinobatan town, was pessimistic about prospects of survivors being found. "It's almost impossible. They have been buried under sand and boulders. I don't think they can survive. It's impossible for anyone to survive."

He said 186 bodies have been recovered and more than 300 were still missing in his village alone.

President Gloria Macapagal Arroyo declared the area a national disaster on Sunday, freeing up government funds to bolster aid efforts.

"We are no strangers to this kind of tragedy, and we have always been able to recover and become stronger," she said Monday.

Arroyo said she instructed the Department of Environment to step up a project to map all hazardous areas, like Mayon, to help forewarn communities of possible dangers.

"We must not leave things to fatal luck when we can develop the tools to prevent harm," she said.

Fernando Gonzalez, governor of worst-hit Albay province, said the ground was too slippery for backhoes.

"There's no choice but to dig by hand," he told Radio DZBB. "Practically speaking, we are not very optimistic we'll find survivors."

In Vietnam meanwhile, authorities evacuated tens of thousands of people from the path of Typhoon Durian, though its winds had diminished considerably since its assault on the Philippines.

Durian lashed the volcano Thursday with 165 mph winds and a five-hour deluge that dislodged tons of volcanic debris from the slopes. Walls of mud and boulders destroyed nearly every standing structure in their path.

"It was like bowling," said Guinobatan Vice Mayor Gene Villareal.