BOGOTA, Feb. 4 (Xinhua) -- Rescuers have brought out 28 dead bodies from a coal mine in northeastern Colombia where an explosion trapped 32 miners on Saturday, Alvaro Uribe, Colombia's president who has traveled to the scene, said on Sunday.

    "This tragedy hurts us all," Uribe said. "Four miners remain to be rescued," he added. Rescuers estimate that these four are trapped 400-meters deep in the San Roque y La Preciosa mine, in Sardinata, a town in Norte de Santander department.

    Firefighters, rescue workers from the Civil Defense Authority and the Red Cross, and police officers are continuing rescue work at the scene despite the difficult conditions caused by the explosion, which appears to be the result of a gas buildup.

    "The Attorney General's office is working a certification process to identify the victims," Uribe said at the disaster site, some 600 km from Bogota, Colombia's capital.

    It is also investigating the mine owners to see if its exploitation permits were up to date, and if it had the correct mine security licenses, he said.

    There are 200 coal mines in this area, which borders Venezuela, some with only the most basic standards.

    Rescue work has been hampered by high concentrations of methanegas in the area, which means that a spark could set off a new explosion, rescuers said.

    Only one miner was rescued alive: Manuel Jose Mendoza Murillo, who died Saturday of massive burns in the Saludcoop Clinic in regional capital Cucuta.

    On Saturday, the Mines and Energy Ministry promised to step up vigilance on all the nation's mines, especially subterranean ones. It added that if the mine company did not have its licenses in order it would be closed.

    Colombia's worst mine accident was in November 2001, when a gold mine collapse killed 40 and injured 22.