BOGOTA: At least six miners were killed when an open-pit gold mine collapsed in a remote corner of Colombia's Nariño province, authorities said.

Jorge Tovar Castillo, a disaster response official in Nariño, said on Monday that an additional 12 to 15 miners have been reported as missing following the accident in the municipality of Santa Barbara de Iscuande. He said municipal authorities were handling the response to the accident but added that communication had been difficult.

Santa Barbara de Iscuande is surrounded by dense rainforest and can only be reached by boat or small aircraft.

“We are waiting for their next report,” Tovar Castillo said. “We are waiting to see if they require additional support.”

In a message on X, Nariño's governor, Luis Alfonso Escobar, said the gold mine that collapsed was an “informal” mine.

Hundreds of small mines in Colombia operate without government permits, and some are controlled by rebel groups.

“At this moment, our priority is to save lives, accompany families and guarantee an opportune response to this painful tragedy,” Escobar wrote on X.

Besides being difficult to reach, Santa Barbara de Iscuande also faces security problems.

Two rebel groups reportedly operate in the area, including the Jacobo Arenas Block, a group led by former members of the Revolutionary Armed Forces of Colombia (FARC) who refused to join a 2016 peace deal with Colombia's government.

In a statement, Colombia's Ombudsman's Office urged armed groups in the area to allow humanitarian aid to reach the small town.

“All of our efforts must go towards protecting lives and tending to this emergency,” the office said on X.