A former regional coordinator of jailed Russian opposition activist Alexei Navalny was sentenced to nine years in prison for participating in an extremist organization, the activists allies announced Monday.Vadim Ostanin, 46, was detained in December 2021 alongside five other Navalny allies across Russia when the authorities blacklisted the Kremlin critics activist network as extremist.Ostanin had served as the coordinator of Navalnys political network in the Siberian city of Barnaul.The Russian authorities opened a retroactive criminal case into Navalnys network in September 2021, prompting many of its members to flee Russia.Prosecutors had requested an 11-year prison sentence for Ostanin, according to the Sibir.Realii news website.While in pre-trial detention, the former Navalny coordinator said his health had deteriorated due to poor conditions and accused the authorities of mistreatment.Prominent human rights group Memorial recognized Ostanin as a political prisoner, according to the activist news website Activatica.Ostanins conviction comes a month after another key Navalny ally, Liliya Chanysheva, was sentenced to seven-and-a-half years in prison on similar extremism charges.