Alexei Navalny, 47, felt unwell after a walk on Friday and lost consciousness. The ambulance that arrived at the penal colony where he was serving his sentence tried to revive him but he died.
The opposition's spokesperson, Kira Yarmysh, said on X, formerly Twitter, that her team had no confirmation of the death. The opponent was serving a 19-year sentence for charges of extremism, the prison service said. Navalny had been in prison since January 2021, when he returned to Moscow after recovering from a nerve agent poisoning.