Pope Francis today expressed his condolences to the victims of Thursday’s mine explosion in Siberia that claimed at least 52 lives, including both miners and rescuers. The tragedy occurred at the Listvyazhnaya mine in the Kemerovo region.

The Pope’s condolences came in the following telegram to Russian President Vladimir Putin, signed by Vatican Secretary of State Cardinal Pietro Parolin:

HIS EXCELLENCY VLADIMIR PUTIN

PRESIDENT OF THE RUSSIAN FEDERATION

HAVING LEARNED WITH SADNESS OF THE TRAGIC MINE EXPLOSION IN SIBERIA, HIS HOLINESS POPE FRANCIS SENDS HIS CONDOLENCES TO YOU AND THE RUSSIAN PEOPLE. HE OFFERS THE ASSURANCE OF HIS PRAYERS FOR ALL WHO HAVE DIED AND FOR THOSE WHO MOURN THEIR LOSS. UPON ALL INVOLVED IN THE RECOVERY EFFORTS HIS HOLINESS INVOKES THE STRENGTH  AND PEACE OF ALMIGHTY GOD.

CARDINAL PIETRO PAROLIN SECRETARY OF STATE

Sky News reported that the explosion was caused by a methane gas leak about 820 feet underground. A total of 285 people were in the mine at the time of the explosion; 239 miners were successfully led to the surface.

Thursday’s explosion was the deadliest mine accident in Russia since 2010 when two methane explosions and fire killed 91 people according to Sky.

A criminal investigation into the blast has been launched. Officials say the mine’s director, along with two senior managers, have been detained.

President Vladimir Putin has offered his condolences to the victims’ families and three days of mourning have been declared in the region.