The explosion happened on Saturday afternoon at the Las Quintas mine in Pueblo Viejo, a village in Cucunuba municipality, said Jorge Emilio Rey, governor of the department of Cundinamarca.

“For now, four workers are reported trapped,” Rey posted on X.

The Cundinamarca Risk Management Office said it was “responding to the emergency”.

Local media reported that the workers were believed to be about 500 meters (1,650 feet) underground.

The cause of the blast was not immediately clear, but mining accidents are common in this region of Colombia, often due to poor ventilation at illegal or artisanal operations that operate without permits and fail to meet safety standards.

On May 4, an explosion occurred in another underground coal mine in the municipality of Sutatausa, also in Cundinamarca. Nine people were killed and six were rescued in that incident.