A methane blast ripped through a coal mine in eastern Ukraine early Sunday, killing at least 63 miners in the ex-Soviet nation's worst mining accident in years, emergency officials said.

More than 360 miners were rescued but 37 others remained trapped inside the mine — one of Ukraine's largest and deepest — with a raging fire hampering efforts to save them, officials said.

The explosion occurred around 3 a.m. more than 3,300 feet deep inside the Zasyadko mine in the regional capital Donetsk, the heart of the country's coal mining industry, the Emergency Situations Ministry said.

Authorities evacuated 367 miners. Twenty-eight were hospitalized, the ministry said.

Vitaliy Kvitkovsky, a miner in his thirties, was among those evacuated. He said he had to walk over the bodies of his dead colleagues in order to climb to the surface.

"The temperature increased sharply and there was so much dust that I couldn't see anything," Kvitkovsky said in footage broadcast on Ukraine's Channel 5 television. "So I was moving by touch over dead bodies along the rail track."

The accident — the worst in Ukraine in seven years — highlighted the lack of attention to safety in a country with some of the world's most dangerous mines.

President Viktor Yushchenko blamed his Cabinet for not doing enough to reform coal mining and ordered an official panel to investigate the accident and bring those responsible to account.

Local authorities declared three days of mourning for the dead miners.

Dozens of teary-eyed relatives gathered at the mine's headquarters in Donetsk waiting for news on their loved ones. As grim-faced officials emerged to announce the names of the workers found dead, the relatives broke into sobs and cries, some fainted.

Natalia Piskun, a middle-aged woman, who waited for news on her husband believed trapped inside the mine, said she would never forgive the mine's director, if her husband was found killed.

"If, God forbid, he is lost, I promise I will, if I manage, I will bite this fat beast on his leg! I promise, I swear to you," Piskun, her face distorted by anger and pain, told AP Television News.

It was the deadliest mine accident in Ukraine since an explosion at the Barakova mine in the eastern Luhansk region killed 81 miners in March 2000.

Prime Minister Viktor Yanukovych, a native of the mining region, visited the site about 450 miles southeast of Kiev, pledging to help victims' families.

Yanukovych said a safety watchdog had reported that miners were working in accordance with norms. "This accident has proven once again that a human is powerless before the nature," he said.

Experts say Ukraine's mines are dangerous largely because they are so deep, typically running more than 3,280 feet underground. In comparison, most European coal beds lie at a depth of 1,640 to 1,970 feet.

Methane is a natural byproduct of mining, and its concentration increases with depth. More than 75 percent of Ukraine's some 200 coal mines are classified as dangerous due to high methane concentrations.

Mines must be ventilated to prevent explosions, but some rely on outdated ventilation equipment, officials said. Safety violations and negligence add to the problem.

Last year, a blast at the mine killed 13 workers. In 2002, an explosion killed 20 and 54 died in a similar explosion in 2001. In May 1999, 50 miners were killed in a methane and coal dust blast there.

Since the 1991 Soviet collapse, more than 4,700 miners in Ukraine have been killed. For every 1 million tons of coal brought to the surface in Ukraine, three miners lose their lives, according to official data.

Despite the dangers, there is growing appetite for Ukraine's rich coal reserves, particularly amid rising natural gas prices. The government has called for production to be increased by a third to 80 million tons this year.