At least six miners were killed while three others trapped after an explosion inside a coal mine on Friday (local time) in Colombia.

The authorities have begun an investigation to establish the causes of the incident, reported Xinhua. Efforts are underway to rescue the trapped workers.

Angelmiro Berbesi, director of the Risk Management Office in the municipality of El Zulia, was quoted as saying that the explosion apparently occurred due to the accumulation of gases inside the mine.