Officials called off the search yesterday for 15 people missing after deadly landslides in Guatemala, fearing fresh avalanches of mud after the heaviest rains in 60 years.

Rescuers had just resumed their grim task of digging for corpses in a ravine next to the Pan-American Highway when officials decided the sodden terrain was unsafe.

"The search has been called off because of the condition of the ground," said David de Leon, a spokesman for the government's emergency management office CONRED.

Dozens of rescuers were buried alive by mud on Saturday as they tried to find victims of an earlier landslide that swept a bus and five other vehicles off the highway.

The overall toll from the torrential early season rains stands at 45 in Guatemala and three in southern Mexico, but with at least 15 still feared to be entombed in mud off the Guatemalan highway that figure could rise.

The rains triggered almost 200 landslides and collapses, causing at least $500 million in damages, according to the Guatemalan government, which ordered three days of national mourning and declared a state of emergency.

President Alvaro Colom said Sunday that the tragedy was made worse by a shortage of government funds after tropical storm Agatha, which killed 165 people and left thousands homeless in May.

The U.S. yesterday offered $4.38 million in aid to Guatemala, while the United Nations said it would send 20,000 food rations to help those affected by the floods.

Many of the dead perished Saturday when new landslides engulfed them while they tried to help dig out buried motorists and passengers. Only 25 of the 40 people believed to have been buried at the site have been retrieved.

"We brought shovels and spades and we were starting to help when another landslide came," said Manuel Sohom, who lost his 15-year-old son. They were only a few metres away from each other but "it all happened so fast we didn't have time to do anything," Sohom said through tears.

"The mud covered me up to my chest and I was able to get out, but the others were completely buried and my son remained under the earth."