Jailed Russian opposition politician Vladimir Kara-Murza has been transferred to a new prison facility with considerably harsher conditions, Novaya Gazeta reported on Tuesday.

Kara-Murza, who is serving a 25-year prison sentence for his outspoken criticism of the Russian invasion of Ukraine, is now in a high-security prison cell in the Siberian city of Omsk in conditions that have been likened to long-term solitary confinement, similar to the ones in which opposition politician Alexey Navalny was placed last year.