Jailed Russian opposition leader Navalny dies

Alexei Navalny, Russian President Vladimir Putin's most formidable opponent, collapsed and died yesterday after a walk at the "Polar Wolf" Arctic penal colony where he was serving a three-decade jail term, the Russian prison service said.

The death of Navalny, a 47-year-old former lawyer, robs the disparate Russian opposition of its most courageous and charismatic leader just as Putin prepares for an election which will keep the former KGB spy in power until at least 2030.

Western leaders and dissidents paid tribute to Navalny's courage as a fighter for freedom. Some, without citing evidence, bluntly accused the Kremlin of murder and said Putin should be held accountable for the death.

Navalny rose to prominence more than a decade ago by speaking publicly - and documenting - what he said was the vast corruption and opulence among the "crooks and thieves" who ran Putin's Russia.

The Federal Penitentiary Service of the Yamalo-Nenets Autonomous District said in a statement that Navalny felt unwell after a walk at the IK-3 penal colony in Kharp, about 1,900 km northeast of Moscow into the Arctic Circle.

He lost consciousness almost immediately and died shortly afterwards despite the efforts of the prison's medical team and ambulance staff, the prison service said. Attempts to resuscitate him failed, it said.

The Kremlin said Putin, who was visiting factories in the Ural mountains, had been informed.

Navalny's wife, Yulia, said she could not be sure her husband was dead because "Putin and his government... lie incessantly".

But if her husband were indeed dead, she said, speaking at the Munich Security Conference, Putin and his entourage "will be punished for what they have done to our country, for what they have done to my family, for what they have done to my husband".

"His death in a Russian prison and the fixation and fear of one man only underscores the weakness and rot at the heart of the system that Putin has built. Russia is responsible for this," US Secretary of State Antony Blinken said shortly before meeting Navalny's wife in Munich.

Navalny's team, who have fled abroad, said it had no confirmation of his death but cast the prison service's statement as a murder confession.