A preliminary hearing will be held in a Moscow court on May 31 in a new criminal case against the jailed Kremlin critic Alexei Navalny on charges that include incitement to extremism, according to official documents posted online.

Navalny, who became known for his satire of President Vladimir Putin’s elite and allegations of widespread corruption, said last month that he had been charged with an “absurd” terrorism case that could result in his conviction to another 30 years in prison.

Navalny he is already serving a total of eleven and a half years for fraud and contempt of court in a maximum security prison colony, charges that he says were fabricated to silence him. His organizations and his Anti-Corruption Foundation have been outlawed in Russia as “extremist”.

According to court documents, the charges against Navalny relate to six different articles of the Russian criminal code, including those for “restoring Nazism”, “organizing an extremist community”, and “public calls to commit extremist acts” as well as inciting citizens to break the law.

Last month, investigators formally linked Navalny supporters to the killing of Vladlen Tatarsky, a well-known military blogger and supporter of Russia’s military operation in Ukraine who was killed in a bomb blast in St. Petersburg. Navalny’s allies deny any connection to his murder.