BOGOTA, Colombia -- A wall of rain-sodden earth collapsed into an illegal open-air gold mining pit in southwestern Colombia on Friday, authorities said. Estimates varied as to the number of people trapped beneath the mud.

Red Cross spokesman Marinson Buitrago put the number of missing at 15 while the state security director reported five missing.

Buitrago told The Associated Press that 31 people were hurt in the collapse, which he said was caused by rains, in the municipality of Santa Barbara de Iscuande in Narino state.

The state security director, Jaime Rodriguez, said by phone that two backhoes were operating at the mine and that Red Cross and civil defence rescue teams had arrived on the scene.

"This is completely illegal mining," he said, adding, that guerrillas of the Revolutionary Armed Forces of Colombia were active in the area.

Colombia's air force said it was sending two helicopters to evacuate the injured.