Nine coal miners have died and six remain trapped underground after an explosion in a coal mine in Colombia, the National Mining Agency (ANM) said.

The explosion near the northern town of El Zulia on Monday was caused by a build-up of gas which caused a fire and the collapse of a tunnel, trapping the miners, officials said.

The surviving miners have been trapped underground for six days.

Families have been waiting desperately for news as rescue efforts continue.

Rescue work was initially hampered by the build-up of gas as well as heavy rains, but some 70 rescuers are now working against the clock to find the remaining miners, AFP reports. (BBC)