A coal mine explosion in eastern Ukraine killed at least 63 miners and left 37 missing on Sunday, an Ukrainian official said.
"The death toll has climbed to 63 and the fate of 37 others is still unknown," said Ihor Krol, chief spokesman of the Emergency Situations Ministry.
The methane explosion occurred at the Zasyadka mine in the Donetsk region at a depth of more than 1,000 meters at 3:11 a.m. local time (0111 GMT), the Emergency Situations Ministry said. The Donetsk region is about 640 km southeast of the capital, Kiev.
The Emergency Situations Ministry said earlier on its Web site that 457 miners were working underground when the blast occurred.
According to the Interfax-Ukraine news agency, Ukraine's Prime Minister Viktor Yanukovych has rushed to the scene and President Victor Yushchenko would fly to Donetsk on Monday.
Sunday's blast was the second mine accident to hit the Donetsk region in two days. On Saturday a miner was killed by falling rocks in another coal mine in the region.
The Zasyadko mine, one of Ukraine's largest, produces up to 10,000 tons of coal every day. But several deadly accidents took place in the coal mine.
A gas leak at the Zasyadko mine in September 2006 killed 13 miners. In 1999 an explosion there claimed 50 lives, while in 2001another blast claimed 55 lives.
Ukraine's most deadly mine accident was in 2000, when 80 miners were killed in an explosion at a colliery in the eastern region of Luhansk.