Another 41 people were injured in the explosions at the Raspadskaya mine in Siberia’s coal-rich Kemerovo region 3,000 km east of Moscow late on Saturday, the Emergencies Ministry said.

Sixty-four miners and 19 rescuers were unaccounted for underground nearly 20 hours after the first explosion just before midnight local time on Saturday. Both explosions were caused by methane gas build-up, the ministry said.

“The situation is clearly serious,” Prime Minister Vladimir Putin said in a televised video conference with rescue leaders. “We need to do everything technically possible so the mine is ventilated in the shortest possible time.”

Rescue operations involving over 500 people were suspended because of dangerous conditions and fears of further explosions after the second blast some four hours after the initial explosion damaged the ventilation shaft.

“We cannot send more people into the mine now, because the concentration of methane is very high and another explosion can occur any time,” Kemerovo region governor Aman Tuleyev told journalists at the site.

Emergency workers were trying to pump air into the mine, described as one of the best equipped in the country by the independent mine workers union.

Miners were led to ambulances with blood-stained clothes as crying relatives gathered nearby, television pictures showed. Smoke poured from the burned remains of an administrative building destroyed in the second explosion.

“Tell us the truth... there’s likely no one alive,” a relative was quoted as saying by Interfax news agency. “Let those who want to go inside (the mine),” shouted another, the mother of a 25-year-old miner with a newborn son.

Itar-Tass quoted a source at the company that owns the mine, also called Raspadskaya, as saying contact with the 19 emergency workers in the mine — three rescue teams — had been lost and their fates were unknown.

At least 13 of the rescued miners were hospitalized in serious condition, the Prosecutor General’s Office said in a statement. Around 300 people emerged from the mine after the first explosion, the statement said.