Local officials feared that a bus was among several vehicles trapped under the mud on a remote road some 169 miles (270 km) southeast of Quito.

"According to what they tell us, the situation is critical," Civil Defense director Ricardo Avendano told Reuters via telephone.

One man was rescued from the mud and taken to a nearby hospital, the agency said.

Marcelo Suarez, director of Civil Defense for Morona Santiago, said that witnesses said several vehicles were trapped under the mud, but rough terrain on the flanks of mountains leading to the Amazon made rescue efforts difficult.

"It would be impossible to quantify how many people are there," he told Reuters via telephone, adding that initial estimates were in the dozens. He said he hoped to better gauge the magnitude of the landslide yesterday morning.

A ticket seller at a bus line in the southern city of Cuenca told Reuters that one of the company's buses was trapped in the landslide, but she did not know how many passengers were on board.

Heavy rainfall is common in Ecuador's Amazon region and on the eastern flanks of the Andes mountains in July and August, local meteorologist Homero Jacome said.