The blast happened on Tuesday morning at the mine in Topaga, some 220km northeast of Bogota.

Topaga's mayor Henry Barrera had already confirmed 11 deaths and said one more miner was still being located, in comments broadcast earlier by local media.

There were conflicting initial reports about how many workers were involved in the accident, with Colombia's mining ministry saying eight had died, four were missing and one was reported injured.

Some local media meanwhile said 14 were involved, while Colombia's Civil Defence said that 12 miners were trapped and one was pulled out uninjured.

According to broadcaster Caracol, the miners were 500 metres deep when the blast was sparked by a build-up of methane gas.

"I am very saddened by what happened in Topaga, it is the most shocking mining tragedy that has occurred in Boyaca," Governor Ramiro Barragan said on Twitter.

"I want to send a message of strength to the families of the miners who have sadly lost their lives and of the injured."

Serious accidents are frequent in Colombian mines, which often have poor safety standards. Illegal mining in particular is a problem in several Latin American countries.

Authorities gave no indication that the mine in question was an illegal operation.

Australian Associated Press