Hundreds of coal workers are marching through Ukraine's capital in a call for authorities to stop buying fuel from abroad and to guarantee a moratorium on mine closures.

The miners used sticks to bang on helmets and waved flags Thursday as they paraded from government headquarters to the coal and energy ministry, where dozens of policemen were guarding the building.

War against Russian-backed separatists in the east, where Ukraine's most productive coal mines are located, forced the government over the winter to seek supplies from overseas providers.

Participants in the Kiev rally, many of them from eastern regions of Ukraine, demanded the resignation of the energy and coal minister. The minister had been due to travel to the United States, but that trip has been cancelled.