Russia has outlawed Navalny’s organisation as part of a crackdown on dissent that’s worsened since the war in Ukraine.

Ostanin was arrested in December 2021 and held in Moscow before being transferred to the Siberian city of Barnaul, where he stood trial on Monday.

Ostanin, who had run the Anti-Corruption Foundation’s local headquarters in Barnaul, had carried out only “legal political work”, Navalny’s team said on Telegram on Monday.

In a letter, written by Ostanin and published by Navalny’s team, he said: “Upon my arrival in Barnaul from Moscow, without explanation, I was placed in a solitary cell, about six square metres, in a basement with a window covered with debris.”

“About a week later, the cell was flooded with ankle-deep water … in these cells there were rats, ants, spiders.”

Navalny’s team said investigators had pressured Ostanin to admit his “guilt”, but he refused.

Russian prosecutors also found him guilty of involvement in a non-profit group “whose activity involves violence against citizens”.

Last month, another Navalny campaigner, Liliya Chanysheva, was sentenced to seven and a half years for “extremism”.

Last week, Russian state prosecutors asked a court to sentence Navalny to another 20 years in a penal colony on criminal charges, including “extremism”.

For the past month, the Kremlin critic has been on trial behind closed doors at the IK-6 penal colony in Melekhovo, east of Moscow, where he is already serving sentences equal to 11 and a half years on fraud and other charges, he said, to silence him.

Court records show that his new charges relate to six articles of the Russian criminal code, including inciting and financing “extremist activity” and creating “an extremist organisation”.

Navalny’s aides said a verdict will be announced on August 4, but acquittals of opposition figures are unheard of.

In his closing statement, Navalny told the court: “I continue to fight against that unscrupulous evil that calls itself ‘the state power of the Russian Federation’.”

“I am accused of inciting hatred towards representatives of the authorities and special services, judges and members of the United Russia party. No, I don’t incite hatred. I just remember that a person has two legs, conscience and intellect,” he said.

Russia has outlawed Navalny’s organisation as part of a crackdown on dissent that started well before Russia’s all-out war in Ukraine but has intensified since it started.