An explosion tore through a coal mine in remote northeast Colombia on Saturday, burying at least 31 miners in tunnels filled with deadly gases, a rescue official said.

Fernando Rosales, director of civil defense in Norte de Santander state, said emergency crews have not yet been able to enter the mine. He said hopes of finding the miners alive was "discouraging" because of the extensive damage and the trapped gases.

"There is a lot of gas inside and we're in the process of trying to get it out to see if rescue crews can go inside," Rosales told The Associated Press from outside the mine.

Rosales said the 31 missing miners were buried in two separate tunnels.

The morning explosion in the remote hamlet of San Roque, 255 miles northeast of Bogota was caused by "some spark and the gas that was inside" the mine, he said.

Many mines in this Andean nation are makeshift affairs with few or no safety procedures.