Russian authorities announced a new criminal charge against Kremlin critic Alexei Navalny on Wednesday, which could add up to three years to his prison term.
It was the latest move in a crackdown before September's parliamentary election.
Navalny, Moscow's fiercest domestic critic, is serving a 2.5-year sentence for parole violations that he says were bogus.
He was arrested after flying back from Germany where he had recovered from being poisoned with a nerve agent.
Mr Navalny and his allies have faced pressure for years, but his political network was outlawed in June after a court formally designated his anti-corruption foundation and regional campaign groups as extremist.
The Investigative Committee, which looks into serious crimes, said Navalny had been charged with creating an organisation that "infringes on the personality and rights of citizens".
It said his Anti-Corruption Foundation had incited Russians to break the law and take part in unauthorised, illegal protests demanding his release in January.
The opposition politician's allies who post on social media under the name Team Navalny described the accusation as "the latest meaningless charge".
The charge came a day after the Investigative Committee on Tuesday announced a criminal investigation into two close allies of Navalny, who live abroad, for raising funds for his political network.
On Sunday, Russian media outlets reported that politician Lyubov Sobol, another close ally of Navalny, had left Russia and flown to Turkey.
She has not commented on her whereabouts and her colleagues have declined to comment.