Moscow, Russia - Fifty-two people including six rescuers are believed to have died after Thursday's accident in a Siberian coal mine, Russian news agencies reported.
"According to preliminary information, no one is left alive in the mine," state news agency TASS quoted a source in the local emergency services as saying.
TASS and news agencies Interfax and RIA Novosti all reported 52 dead, with TASS and RIA Novosti saying six rescuers were among the deceased.
Officials had earlier reported at least 11 miners and three rescuers dead and said 35 people were unaccounted for after the accident at the Listvyazhnaya mine in the Kemerovo mining region. The mine, near the town of Belovo in the Kemerovo mining region, filled with smoke in the early hours of Thursday with 285 people inside.
Rescuers launched but later called off a search operation, with officials saying there was the threat of an explosion at the mine. The Investigative Committee, which probes major cases, opened a criminal probe into the possible violation of safety regulations that led to deaths.
Investigators said that three people had been detained including the 47-year-old director of the mine and his 59-year-old first deputy.
Mining accidents are fairly common in Russia and across the former Soviet Union as a result of poor safety standards, a lack of oversight of working conditions, and ageing Soviet-era equipment.