Bogota, Apr 21 (IANS): The National Mining Agency of Colombia has confirmed that three of the seven missing miners were found dead after the coal mine explosion in the municipality of Cucunuba.

At least seven miners had been missing after the explosion in the Colombian municipality in the department of Cundinamarca, Governor Nicolas Garcia was quoted by Xinhua news agency as saying.

"We have a report from the rescue team stating that they pulled out alive four trapped miners, who are being taken to the hospital, while we continue the search and rescue for seven other miners," Garcia said on Thursday in a video posted on Twitter.

The explosion occurred at about 1:00 a.m. local time on Thursday in interconnected mines in an area of Pueblo Viejo.

Minister of Mines and Energy Irene Velez detailed on social media that teams from the National Mining Agency, the Civil Defense, the Public Force and the fire department were working on the rescue mission.

"It has been difficult to enter the mines because toxic gases have been discharged, such as carbon monoxide, methane gas and coal dust ... in mines with a depth of more than 900 meters," Captain Alvaro Farfan, representative of the Cundinamarca fire department, told local media.

The official also said that the affected mines were called El Roble, El Condor and El Manto and that the causes of the accident were under investigation.