"The bodies of 21 miners have been discovered as of 4 p.m. Moscow time (1 p.m. GMT)," the ministry said.
The ministry said 68 miners, including five injured, had been rescued up to now from the Ulyanovskaya mine in Novokuznetsk, the largest coal producing center in the Kemerovo Region.
The explosion ripped through the mine at 11:16 a.m. Moscow time (8:16 a.m. GMT), when 186 people were working there.
Rescuers are continuing work at the site. Earlier reports said Emergency Situations Minister Sergei Shoigu would soon fly to Novokuznetsk on President Vladimir Putin's order.
Explosions are not uncommon in Russia's crumbling coal mining industry. But the Ulyanovksaya mine was only opened in 2002. It produces 3 million metric tons of coal annually and its reserves total 210 million metric tons.
