The number of miners and rescuers killed as a fire ravaged a coal mine in Siberia has risen to 51, according to Russian news reports.
The fire broke out at the mine in the northern Russian region of Kemerovo on Thursday, local authorities said.
Eleven miners were found dead while three rescuers also died later while searching for others trapped underground.
Six more bodies were recovered on Friday morning, while 31 people remained missing and were feared to be dead.
Rescuers did however locate one rescuer who survived the disaster on Friday in what has been described as a "miracle".
Authorities had put the death toll at 52 on Thursday evening, saying that there was no chance of finding any more survivors.
The rescue mission had to be halted altogether due to rising levels of carbon monoxide fumes from the fire, and methane buildup posing a risk of explosion.
The Russian Emergency Ministry earlier said in a statement that a total of 239 people had been brought to the surface.
A total of 285 people were in the Listvyazhnaya mine at the time of the incident, Kemerovo Governor Sergei Tsivilyov said on Telegram.
Tsivilyov said in another Telegram post that 63 people with injuries have sought medical assistance. Regional officials have declared three days of mourning for the victims.
The cause of the fire remains unknown, but Russian media has stated that coal dust caught fire, and that smoke quickly filled the Litsvyazhnaya mine through the ventilation system.
However, Russia’s Deputy Prosecutor General Dmitry Demeshin told reporters that the fire most likely resulted from a methane explosion caused by a spark.
Russia’s Investigative Committee has launched a criminal investigation into suspected violations of safety regulations and have detained the mine director and two senior managers.
President Vladimir Putin has extended his condolences to the victims' families and ordered the government to offer all the necessary assistance to those who were injured, according to Kremlin spokesman Dmitry Peskov.
After 36 miners were killed in a series of explosions at a coal mine in 2016, Russian authorities analysed the safety of the country’s 58 coal mines and declared 20 of them potentially unsafe.
Accidents in Russian mines are often blamed on poor safety regulations or outdated Soviet equipment.
The deadliest accident in recent years killed 91 people and injured more than 100 in May 2010 at the Raspadskaya mine, which is also in the Kemerovo region.