The morning blast at the Zasiadko mine in the coal-rich Donetsk region was the most serious accident this year in Ukraine's coal mines, which are considered among the world's most unsafe.
The regional Work Safety Department said 257 miners were working underground in the vicinity of the explosion while Ukraine's Emergency Situations Ministry put the figure at 259.
Most of the miners were brought to the surface, where 22 were hospitalized and 22 others found to have suffered light injuries, the ministry said. At least four of the hospitalized workers were in grave condition, the work safety department reported.
The ministry said at least 14 miners were missing, but noted that its figures were preliminary. Earlier, the regional department said 22 workers were missing.
Rescue teams were working in the mine, battling a continuing fire, officials said.
It was not immediately clear what caused the explosion at the Zasiadko mine, which was also the site of a May 1999 methane explosion that killed 50 miners and injured about 40 others.
One miner who escaped the accident unharmed described seeing "piles of bodies" while making his way to the surface. Police surrounded the mine compound and barred reporters from entering. Grim-faced workers and relatives sat outside the mine's main administrative building in Donetsk awaiting the news.
President Leonid Kuchma ordered that a government commission be formed to look into the causes of the accident, said his spokesman Oleksandr Martynenko. Kuchma also planned to visit the mine Monday.
Deputy Prime Minister Volodymyr Semynozhenko, meanwhile, pledged to help the families of the dead and wounded and lamented the deteriorated state of Ukraine's coal industry, the Interfax news agency reported.
"This is a tragedy. We understand once again that that we must re-equip our coal industry both techically and technologically to bring it to a proper level. It is one of the state's priorities," Semynozhenko said.
Ukraine, once the pride of the Soviet Union for its huge coal mining industry, has more than 200 working and mostly unprofitable mines that were devastated by the Soviet collapse in 1991.
After the government of independent Ukraine slashed subsidies to the coal industry, the death rate began to rise. Last year, 318 coal workers died on the job, including 81 killed in a single explosion, and at least 149 have died so far this year.
Most accidents are blamed on outdated equipment and widespread disregard for safety rules. This year's second-deadliest accident was a May explosion at the Kirov mine which killed 10 and injured dozens of workers, also blamed on gross violation of safety rules.
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