“He felt bad after a walk, almost immediately losing consciousness. Medical staff arrived immediately and an ambulance team was called. Resuscitation measures were carried out which did not yield positive results. Paramedics confirmed the death of the convict. The causes of death are being established,” the report said.

The official Kremlin said President Vladimir Putin had been informed of Navalny’s death.

Alexey Navalny, 47, was in the IK-3 penal colony in Kharp, about 1,900 km northeast of Moscow.

The “special regime” or “Polar Wolf” colony is among the harshest in Russia’s prison system, located in a place with severe winters. Most inmates have been convicted of grave crimes. Kharp is about 100 km from Vorkuta, whose coalmines were part of the Soviet gulag camp system.