GUINSAUGON, Philippines (AP) – Rescue workers on Tuesday shifted the focus of their digging for survivors of last week’s landslide in the Philippines away from a spot where they excitedly detected underground sounds they hoped were signs of life from a buried elementary school.

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, swamping the farming village of Guinsaugon in a sea of mud and boulders.

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 93, and about 1,000 were missing and feared dead.

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

Excavations had centered Monday at a site where the school was believed to have stood, 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 move away from 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 … because we really want to hear something,” Farley said. “If there is anything at all, we’re going to go there.”

Trapped survivors of past landslides or earthquakes have sometimes held out for days, communicating with search parties by calling out or tapping on rocks.

But hopes of finding people alive in Guinsaugon have seemed remote because the village was inundated by a dense wall of mud and rock, making it unlikely that many air pockets would form beneath the sodden surface.

Accurate information on the location of structures beneath the mud was hard to come by, as well.

“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.”

Marines and Philippine soldiers, along with local miners, dug into the muck with shovels and moved it with body bags, draining the murky water in large bottles. The search teams moved carefully, unable to work as fast as they wanted for fear that their movements could set off more landslides.

“Safety is an ongoing concern right now because of the rain,” said Marine Capt. Burrell Parmer. “So far, no survivors have been recovered. It’s a sad deal.”

The smell of rotting bodies wafted through the command post of the relief effort, less than a mile from the landslide site.

Under the glare of generator-powered lights, a multinational group of troops and technicians worked until nearly midnight Monday with shovels, rescue dogs and high-tech gear, including sound- and heat-detection equipment. Geologists had warned them not to work through the night because the area was unsafe

With no one left to claim the dead and bodies quickly starting to decompose in the tropical heat, victims were being buried in mass graves. Some officials suggested leaving the village as a massive cemetery because digging out bodies was too difficult and dangerous.