KIEV, March 25 - Ukraine’s coal sector is under pressure after coal miners at 15 state-owned coal companies went on strike to demand payment of back wages, a trade union said Wednesday.

Thousands of coal miners in Volyn, Lviv and Donetsk regions blamed Energy and Coal Industry Minister Volodymyr Demchyshyn for the sector woes.

“The miners don’t know where to put coal they have produced,” Mykhaylo Volynets, the head of the Independent Coalminers Trade Union, said. “Demchyshyn is importing power from Russia, while our miners can’t find buyers for their own coal.”