Russian investigators on Tuesday launched a new "extremism" probe against jailed Kremlin critic Alexei Navalny and his top allies that could see the opposition leader spend up to 10 more years in jail.
The fresh probe comes after Navalny's groups were already banned as "extremist" earlier this year and President Vladimir Putin's party this month shored up another five years in control of the lower house of parliament.
The Investigative Committee, which probes major crimes in Russia, said in a statement that by 2014 Navalny had "created an extremist network and directed it" with the aim of "changing the foundations of the constitutional system in the Russian Federation".
Navalny, 45, and his top allies Leonid Volkov and Ivan Zhdanov are suspected of having run an "extremist network", while Lyubov Sobol and a number of his other allies are accused of taking part.
Investigators accused Navalny and his allies of setting up a number of social media accounts and the website of Navalny's banned Anti-Corruption Foundation (FBK) "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 activities were also aimed at "destabilising the situation in the regions", they added, and "shaping public opinion about the need for a violent change of power".
Investigators also said calls for "extremist and terrorist activities" were common at regular street protests organised by Navalny and his allies.
More jail time
If convicted, Navalny, Volkov and Zhdanov could face six to 10 years in prison, while Sobol and the other activists risk two to six years behind bars.
Navalny, Putin's most vocal domestic critic, was detained in January and sentenced to 2.5 years in a penal colony the following month.
He saw his nationwide network of political offices and FBK declared "extremist" and banned in June.
In recent months, the opposition leader and his allies have become targets of numerous probes that they and their supporters describe as the Kremlin's revenge for challenging Putin's two-decade-long rule.
Most of his top allies including Volkov and Zhdanov have fled the country.
The latest probe comes after Putin's deeply unpopular ruling United Russia party won a sweeping majority in the lower house State Duma earlier this month.
Anyone associated with Navalny's banned groups was kept from running in the elections, while his allies called for opposition supporters to back other candidates who could potentially defeat United Russia.
Russia's opposition accused the authorities of mass voter fraud in the election and in a message from prison last week Navalny said the polls had been "stolen".