Jailed Kremlin critic Alexey Navalny is facing a new criminal probe by Russian investigators that could lead to 10 more years in prison.

The investigation, launched Tuesday by the Russian government’s Investigative Committee, which probes major crimes, accuses Navalny of creating and directing an “extremist network” the goal of which was “changing the foundations of the constitutional system in the Russian Federation,” according to a statement by the committee.

Investigators also accuse Navalny and his allies of setting up social media accounts to promote Navalny’s banned Anti-Corruption Foundation “in order to promote criminal activity.”

“The illegal activities of the extremist network were aimed at discrediting state authorities and their policies,” investigators said.

The probe comes after Russian President Vladimir Putin’s party won lower house parliamentary elections earlier this month.

Navalny’s allies were banned from running in the elections, and last week, Navalny, in a message from prison, said the election had been stolen.

Navalny, 45, is currently serving a two-and-a-half year sentence on a 2014 embezzlement conviction that was widely seen as politically motivated.   

The sentence was suspended but Navalny was arrested for parole violations in January when he returned to Russia from Germany, where he was recovering from what he said was a nerve agent attack by the Kremlin. Russian officials deny his allegation.  

In June, Navalny’s foundation was outlawed as “extremist,” and authorities blocked websites run by his network, charging them with distributing propaganda. Two of Navalny’s top allies, Ivan Zhdanov and Leonid Volkov, are also facing criminal investigations.