Jailed Putin opponent Alexei Navalny has died, Russian media says

• Imprisoned Russian opposition politician Alexei Navalny has died, Russian state news agency Tass reported on Friday, citing the prison service of the Yamalo-Nenets region.
• CNBC could not independently verify the report.
• Navalny, 47, was an anti-corruption campaigner and one of Russian President Vladimir Putin's most vocal critics.

Imprisoned Russian opposition politician Alexei Navalny has died, Russian state news agency Tass reported on Friday, citing the prison service of the Yamalo-Nenets region where he had been serving his sentence.

The prison service reportedly said the cause of Navalny's death was still to be established.

Alexey Navalny's spokesperson, Kira Yarmysh said in a Google-translated update on the X social media platform that "We don't have any confirmation of this yet. Alexey's lawyer is now flying to Kharp. As soon as we have any information, we will report it."

CNBC could not independently verify the report.

Navalny, 47, was an anti-corruption campaigner and one of Russian President Vladimir Putin's most vocal critics. He was serving a 19-year jail term on charges of extremism.

Navalny "felt unwell after a walk, almost immediately losing consciousness," Interfax reported, citing a statement from the office for the prison service of the Yamalo-Nenets region.

The statement said "all the necessary resuscitation measures were carried out, but did not yield positive results." It added that an ambulance was called and emergency doctors later confirmed Navalny's death.

The Investigative Department of the Investigative Committee of Russia for the Yamalo-Nenets Autonomous Okrug region said Friday on Telegram that it is organizing a procedural check into the death of Navalny, according to a Google-translated