Eleven Polish nationals and two Czech miners died in a methane blast more than 800 metres underground at the mine, which is situated close to the Polish border.
A search of the scene had to be abandoned due to a raging fire and zero visibility, according to the mine’s state-run operator, OKD.
It is the worst mining disaster to hit the Czech Republic since 1990, when 30 miners died in a fire at a mine near Karvina.
IndustriALL’s assistant general secretary, Kemal Özkan, said:
“We are shocked and saddened at this terrible waste of life. All mining deaths are avoidable and safety must come first at all costs. As a global union representing miners all over the world, we offer our deep condolences to the victims’ families and all those affected by this tragedy.”