Colombian rescue workers and miners remove the bodies of victims after the explosion that ripped through a coal mine in the municipality of Amaga, Antioquia department, northeast Colombia on June 17, 2010. (Raul Arboleda/AFP/Getty Images)

At least 18 miners were killed, and dozens are still missing after an explosion in a Colombian coal mine, just south of Medellin, on Wednesday.

According to Colombian media, as of Thursday afternoon 18 bodies have been found, but at least 53 miners are still trapped.

President Alvaro Uribe expressed his "pain" over the tragic incident, which took place in the San Fernando-Mine, in the mountainous area of Antioquia.

An explosion caused the collapse of a 1.3 mile-long shaft that normally provides access to a depth of 500 feet.

The rescue is hampered by a large concentration of methane gas. More than 100 rescue workers are being assisted by a special army unit in finding the trapped miners.

The explosion occurred while shifts were changing. At the time, between 70 and 80 miners were down in the mine.

Two wounded miners were able to reach safety on their own. So far only one miner has been found alive, and all victims were severely burned by the explosion. According to AP, an accident in August 2009 in the same mine killed nine people.