SAO PAULO, Brazil (AP) _ Rescue workers Wednesday dug through tons of dirt and debris from a landslide that buried a Sao Paulo shantytown, killing at least three people, injuring dozens and leaving at least 90 missing.

However, officials said they had little hope of finding survivors from Tuesday's accident, which occurred after a 100-foot-high hill of dirt from construction sites collapsed at the Nova Republica slum.

Fire Department Maj. Luiz Roberto Carchedi said shantytown community leaders estimated more than 90 people were missing.

''But that does not mean they are all dead,'' Carchedi said, ''because we are sure that many of those unaccounted for are in temporary shelters.''

''We may never know how many people were killed,'' he added.

At least three people died and dozens of slum dwellers were injured Tuesday evening in the landslide, fire officials said.

''We heard a loud roar and the ground shook and we ran for the door,'' Maria dos Prazeres, a survivor, said in a televised interview. ''We just had time to move before the walls came crashing down on us.''

A total of 56 wood and brick shacks were buried, Lt. Francisco Tenorio de Albuquerque of the fire department said.

''The chances of finding anyone still alive beneath all this rubble are extremely remote, but we will continue searching because we can never give up hope,'' Carchedi said.

Several of the shacks were buried underneath 45 feet of dirt, Carchedi said.

Firemen, policemen, civil defense workers and volunteers using bulldozers, backhoes, shovels and in many cases their bare hands worked nonstop Wednesday digging through mud in search of victims.

Four specially trained police dogs scoured the area looking for survivors.

Carchedi, a rescue coordinator, said three bodies had been pulled out and that about 20 people were treated for injuries at an emergency treatment center set up near the slum.

Survivors at the scene said about 400 people lived in 100 shacks in the neighborhood.

The landfill was made of dirt excavated from construction sites around the city and illegally dumped next to the shantytown, said Geraldo Jacob, an employee of the Public Works Department in Sao Paulo.

He said the earth was loose and slid away because of underground streams that eroded its base.

Fernando Luiz Prandini, a geologist of the Sao Paulo University's Institute for Technological Research, surveyed the area and estimated about 600,000 tons of earth collapsed.