Emergency workers had recovered 31 bodies later Tuesday and were seeking five others in the Krasnolimanskaya mine, said Andrey Klyuyev, Ukraine's Deputy Prime Minister in charge of investigation of the blast.
"We will keep searching," Kluyev told reporters.
The blast Monday night hit a section of the mine in the Donetsk region, about 3,180 feet below the surface, said Oleh Venzhyk, a spokesman for the Ministry for Emergency Situations.
Dozens of rescue teams searching for dead and injured miners were being hampered by raging fires, high concentrations of poisonous gases, heavy smoke and temperatures of up to 120, a rescuer who gave his name only as Volodymyr said by telephone.
"Rocks and debris make our job incredibly difficult ... it's a complete mess down there," Volodymyr said.
Meanwhile, rescuers announced that they will start pumping nitrogen and flooding the parts of the burning shaft in an attempt to put out the fire.
At the time of the explosion, 48 miners were at work; 12 managed to escape.
Prime Minister Viktor Yanukovych, Kluyev and other top officials traveled to the mine to monitor rescue efforts. The government also announced it will allocate some $470,000 in financial aid to the families of dead and injured miners.
Ukraine's mines are considered to be among the world's most deadly due to high concentrations of methane gas, frequent violations of safety rules and outdated equipment. According to the Fuel and Energy Ministry, more than 75 percent of Ukraine's 200 coal mines are classified as "dangerous."
The Krasnolimanskaya mine is considered one of the most perilous mines in Ukraine due to frequent methane leaks. Three years ago, nine Krasnolimanskaya miners died in a methane blast. The mine is also one of Ukraine's most profitable, producing more than 10,000 tons of high-quality coal daily.
The explosion is the deadliest mining incident in Ukraine in two years. In July 2002, 33 miners died in a fire and in 2001, 55 died in a gas explosion. Four years ago, 81 miners were killed in an explosion in a mine in the Luhansk region, the deadliest accident in decades.
At least 267 miners died in Ukraine's mines last year, according to the State Labor Protection Committee. More than 3,700 have been killed since 1991. Authorities estimated that on the average, some three Ukrainian miners die for each million tons of extracted coal.