Kiev - An underground explosion killed five Ukrainians attempting to remove coal and scrap metal from an abandoned mine, a Ministry of Emergency Situations official said Monday.

The blast took place in a locked-down shaft near the village Trubne, in the eastern Luhansk province.

It was not immediately clear whether the victims died in the explosion or the ensuing below-ground fire, Channel 5 television reported.

Investigating police said a methane gas buildup and unsafe use of metal objects was a probable cause of the explosion.

All five had been area residents, and the shaft had been targeted by illegal miners in the past, Channel 24 television reported.

The victims reportedly armed with picks and shovels overcame locks and barriers in order to break into the mine. A spark caused by digging may have triggered the explosion, according to the report.

Ukraine's government operates some of the world's deepest and most dangerous coal mines, and has been hard-pressed to close all but the worst of the pits because of unemployment fears.

The former Soviet republic's depressed metals industry has nonetheless shed tens of thousands of jobs in recent months. Some unemployed coal miners have resorted to mining the closed shafts illegally in order to support their families. (dpa)