A methane explosion 800 meters underground at OKD a.s.'s CSM coal mine in the Czech Republic killed 13 miners and severely damaged parts of the mine, Reuters reported Dec. 21.

Twelve of the victims were Polish while one was Czech, according to the report.

OKD mining company spokesman Ivo Celechovsky said that underground work was stopped immediately and miners were evacuated to the surface.

The accident is the worst mining disaster in the country since 1990 when 30 miners were killed in a fire at a mine in the same region as CSM, according to CTK news agency.

OKD Managing Director Boleslav Kowalczyk said the methane sensors in the mine did not detect anything unusual before the blast. A rescue attempt for eight missing miners was called off, with Kowalczyk saying, "Unfortunately, we have reached a point where it was impossible to move forward, because there was a fire raging and zero visibility."