KIEV, March 6 - The March 2 accident at Stepova coal mine of Lvivvuhillia state company, in which eight people died, happened during repair efforts, but the exact reason behind the methane blast is still being probed, Deputy Prime Minister, Minister of Regional Construction, Housing and Utilities Services Hennadiy Zubko said.

"This is the first accident, when such a tragedy has occurred in western Ukraine," Zubko said at a briefing in Kiev on Monday following a meeting of the governmental committee which is dealing with the investigation into the causes behind the accident at Stepova coalmine.