At least six miners were killed and three others trapped after an explosion inside a coal mine on Friday in Colombia.

The authorities have begun an investigation to establish the causes of the incident, according to a media report.

Search operations are underway for trapped workers.

Angelmiro Berbesi, director of the Risk Management Office in the municipality of El Zulia said that the explosion apparently occurred due to the accumulation of gases inside the mine, according to ANI report.

In April, eleven workers were killed and four injured in an accidental explosion at a Colombian coal mine in Cucunuba, near Bogota.

In 2017, the explosion took place in the Cucunuba municipality in Cundinamarca province that left eleven miners dead.

An area where illegal underground coal mining is widespread and accidents are not uncommon.