Manuel Sohom Ixmata, centre, relative of a mudslide victim, reacts in Nahuala, western Guatemala on Sunday. (Moises Castillo/Associated Press)

Torrential rains from a tropical depression caused landslides that have killed at least 38 people in Guatemala — some of them rescuers who had come to save people trapped by a wall of mud.

In the village of Nahuala, about 200 rescue workers searched through mud and rocks for bodies on Sunday after two landslides in the same spot killed at least 20 people along a highway leading northwest of the capital toward Mexico.

Another slide closer to Guatemala City killed at least 12.

A slide Saturday afternoon had trapped vehicles on the Inter-American highway, and some of the people who came to rescue them were themselves caught by a second slide, officials reported.

"Under the earth there is a bus that carried we don't know how many people, and there are those who tried to help the victims of the first slide," regional fire department Maj. Otto Mazariegos said.

Rescue crews have recovered 20 bodies from that site, fire department spokesman Jose Rodriguez said, adding at least 60 people are missing.

A few hours earlier, a landslide on the same highway partially buried a bus, killing 12 people.

On Sunday, President Alvaro Colom visited the area of the mudslides and said Monday would be declared a national day of mourning. He asked local officials to determine the precise number of missing.

Speaking a day earlier, even before news of the second highway slide was known, Colom said, "It is a tragic day. Today alone 18 people have died, 12 buried by a hill when the travelled in a bus." Four children and two adults died in slides elsewhere, he said.

Fearing more slides, the president told officials to close the highway.

"There are several hillsides that are loose and could fall, so we ask the population to not go out, to avoid moving along the highways," he said — not long before new slides took more lives.

Heavy rains from a tropical depression have pelted Guatemala for days, unleashing deadly mudslides in several areas, cutting highways and forcing officials to evacuate thousands of people.