MOSCOW, Russia (AP) — A fire at a coal mine in Russia’s Siberia killed 11 people and injured more than 40 on Thursday, with dozens of others remaining trapped, authorities said.

The blaze broke out in the Kemerovo region in southwestern Siberia. Russia’s state Tass news agency reported, citing an unnamed emergency official, that coal dust caught fire, and smoke quickly filled the Listvyazhnaya mine through the ventilation system.

Efforts to rescue those trapped in the mine were halted on Thursday afternoon because of an explosion threat, and rescuers were rushed out of the mine, administrators of the mine told the Interfax news agency.

A total of 285 people were in the mine at the time of the incident, Kemerovo Governor Sergei Tsivilyov said on his page on the messaging app Telegram. He said 35 miners remained trapped underground, and their exact location was unknown.

Tsivilyov said in another Telegram post that a total of 49 people with injuries have sought medical assistance. He had earlier reported a toll of 60 injured people and hasn’t offered any explanation for the revision.

Earlier Thursday, Russia’s acting minister for emergency situations, Alexander Chupriyan, said 44 miners have been hospitalised with injuries. The difference in injury tolls reported by different officials couldn’t be immediately reconciled.

Russia’s Investigative Committee has launched a criminal probe into the fire on charges of violating safety regulations that led to deaths.

President Vladimir Putin extended his condolences to the families of the killed miners and ordered the government to offer all necessary assistance to those who were injured.