(CNN) -- Emergency workers were racing Tuesday to find 12 miners missing after an explosion in a Ukrainian mine, which killed at least one person and injured 29 others.
Ukrainian officials have expressed fears about flooding in the mine. A rescue committee is operating around the clock to find the miners, government officials told Russia's Interfax news agency, and psychologists are available to the miners' families.
First Deputy Prime Minister Oleksandr Turchynov said Sunday that human voices could be heard coming from 700 meters (2,300 feet) below ground.
The explosion was the most powerful in the history of the Ukrainian coal industry, said Igor Kroll, a spokesman for Ukraine's Ministry of Emergency Situations. Officials have said they know it was a methane blast, but they don't know what caused it.
The blast happened early on Sunday at the Karl Marx mine in Yenakiyeve, in the Donetsk region in eastern Ukraine, which lies about 640 kilometers (400 miles) southeast of the capital, Kiev.
The 12 missing miners are among 42 who were in the mine at the time of the blast. One was killed, 24 were rescued, and five were above ground but were injured, Kroll said.
In all, 29 miners have been taken to hospital, he said.
The 24 who were rescued had tried to get as close to the surface as possible before they were rescued, Kroll said.
The explosion was the latest in a series of industrial accidents for Ukraine's mining industry. The government said it had opened a criminal investigation because the mine was operating despite a recent ban.
Turchynov said a state industrial safety watchdog on Friday examined the mine -- where another explosion killed seven in 1999 -- and ordered it to be shut down.
"If there is information that the mine kept operating and producing coal despite the ban, it will be a matter for the office of the prosecutor general to take up," Turchynov told a briefing. "Undoubtedly there will be a very strict punishment."
Ukraine has some of the world's most dangerous mines with more than 4,800 miners in Ukraine killed since 1991. Officials say that for every 1 million tons of coal brought to the surface in Ukraine, three miners lose their lives.
CNN's Mike Sefanov in Moscow contributed to this report.