Sergei Udaltsov, leader of the opposition Left Front movement, said he was under investigation for allegedly discussing revolutionary ambitions with political leaders Georgia. The investigation was launched after a low-quality video surfaced that showed him meeting with Georgian leaders.
He told state-run news agency RIA Novosti the footage was a forgery, saying it's part of a "wave of repression" launched by the Kremlin.
Vladimir Markin, a spokesman for the Russian investigative committee, told news agency RT, however, there were no signs the video was edited.
"Those who think they can with impunity organize mass disorder, plan and prepare terrorist attacks and other acts that threaten the lives and health of Russians, you underestimate the Russian special services' professionalism," he said.
Arrested on several occasions for his opposition activity, Udaltsov told the Russian bureau of Radio Free Europe/Radio Liberty in September there should be early elections to unseat President Vladimir Putin. State Duma elections in December and presidential elections in March, he said, were illegitimate.