Alexei Navalny, a prominent critic of Russian President Vladimir Putin who survived a poisoning and spent months in isolation, died in an Arctic Circle maximum-security prison, the country's state media reported Friday.
The Federal Penitentiary Service of the Yamalo-Nenets Autonomous District, where he was being held, said Navalny, 47, "felt unwell" after he went on a walk and "almost immediately lost consciousness."
No cause of death was detailed. The prison service said it tried to resuscitate him without success. Kremlin spokesman Dmitry Peskov said he had no information about how Navalny died.
Russian dissidents and Western opponents were quick to blame the Kremlin for Navalny's death.