A Russian court placed opposition leader Alexei Navalny under house arrest for at least two months on Friday and barred him from using the Internet or speaking to the media as authorities probe charges of embezzlement brought against him. Kremlin opponents say the move is part of a concerted effort by the government to quash dissent that could be inspired by the recent political turmoil in Ukraine.

The court said Navalny, an outspoken critic of President Vladimir Putin and a leader of anti-Kremlin protests in 2011 and 2012, had violated rules barring him from leaving Moscow.

Navalny, who has been instrumental in rallying Russia’s young Internet generation against Putin’s rule, denounced the ruling as baseless and said it was meant to silence him. Supporters, including members of protest band Pussy Riot, shouted “Freedom!” as he left the courtroom.

“I believe the new measures are based on trumped-up grounds in order to restrict my political activities,” Navalny, 37, said in court.

Opposition activists say the upheaval in neighboring Ukraine, where protests forced President Viktor Yanukovich from power after he scrapped plans for closer European Union ties to move closer to Moscow, has deepened Putin’s determination to prevent any revival of street demonstrations.

They say Putin is also clamping down on dissent after engineering the release of long-jailed oil tycoon Mikhail Khodorkovsky and two members Pussy Riot before the Sochi Olympics, which ended last week.

Navalny, who gained prominence with blog posts alleging government corruption, emerged from the biggest protests against Putin’s 14-year rule as the main opposition leader and a potential future challenger in elections.

He is serving a five-year suspended sentence on a theft conviction that will keep him out of a 2018 presidential vote, and he has been charged with theft and money laundering in a separate case that has not come to trial.