Rescue workers dug grimly Tuesday for a mud-swamped elementary school, but in a different spot from where they excitedly detected underground sounds a day earlier that they hoped were signs of life.

The buzz that fed a sense of urgency Monday evening was gone. Ground-penetrating radar, capable of mapping structures up to 50 feet deep, found nothing.

Hopes of a miracle had focused on the school amid unconfirmed reports that survivors there sent cell phone text messages to relatives shortly after a mountainside collapsed Friday in a wall of mud and boulders that swamped the farming village of Guinsaugon on Leyte island.

But with the only survivors pulled out hours later, the prospects of finding life under mud believed to be more than 100 feet deep were fading by the hour. The confirmed death toll was 107, and about 1,000 were missing and feared dead, said Dr. Adelaida Asperin, a Department of Health official on Leyte island.

The threat of more rain-triggered landslides slowed the search, as did confusion over where to dig and problems dealing with the wet mud.

After another frustrating day, most rescue workers left the site a couple of hours after dark, with a few teams using specialized gear staying behind to take advantage of the silence to listen for sounds under the mud that could be checked later.

Excavations had centered Monday at a site where the school was believed to have sat, with some troops, miners and volunteers digging at a second site, about 200 yards away where some estimated the building might have been carried.

U.S. Marines, digging in shifts of 40 men, worked alongside Philippine troops and technical experts from Malaysia and Taiwan, but finally had to give up on the first site when the holes they created kept collapsing.

"As we'd dig deeper, we'd try to dig wider, but with the rain last night ... there were little landslides happening around us," said Lt. Jack Farley, who was heading the Marine contingent. "The soil here is so unstable."

It also was unclear if the scratching and tapping noises that were heard Monday came from survivors or just ground water or the mud settling.

"A few times we heard something, we think we heard something, because we really want to hear something," Farley said. "If there is anything at all, we're gonna go there."

Accurate information was hard to come by, too.

"Even the local population has kind of lost their bearings," Farley said. "They don't have those terrain features around to distinguish where something really is."

Rescue teams used sensors in an effort to detect sounds and movements similar to those monitored on Monday.

Officials had refused to allow heavy machinery in the disaster zone out of fear it could cause the unstable mud to shift, but with conditions solidifying and shovels making little headway, they brought in a backhoe. It had similar problems with holes that it dug caving in.

Joel Son, head of a rescue team of Filipino miners, said the mud was so deep that searchers had yet to find the school where up to 300 children were in class when the disaster struck.

"Safety is an ongoing concern right now because of the rain," said U.S. Marine Capt. Burrell Parmer, one of hundreds of American servicemen involved in the recovery operation. "So far, no survivors have been recovered. It's a sad deal."

Search teams moved carefully, unable to work as fast as they wanted for fear that their movements could set off more landslides.

Asperin, the Department of Health official, said two children had been isolated and were being treated for chicken pox in evacuation centers where families that lost their homes were staying. She said there was no threat of a disease outbreak at the centers.

Under the glare of generator-powered lights, a multinational group of troops and technicians worked into the night Monday with shovels, rescue dogs and high-tech gear, including sound- and heat-detection equipment.

Some officials suggested leaving the village as a massive cemetery because digging out bodies was too difficult and dangerous. Some unidentified bodies were buried in mass graves.