Police on Wednesday detained about 20 people during a rally in front of the parliament building in Moscow.
Earlier reports said there was a heavy police presence outside the building in central Moscow as lawmakers arrived for the new State Duma’s first session.
The opposition Other Russia movement earlier vowed to prevent MPs from entering the building in protest at alleged fraud in the country’s parliamentary elections earlier this month in which Prime Minister Vladimir Putin’s ruling United Russia party won, albeit with a narrow majority.
Other Russia activist Sergei Aksyonov told the Ekho Moskvy radio station several dozen people were detained at a small rally that drew about a hundred people.
Allegations of fraud in the December 4 vote have triggered the biggest protest movement since Soviet times, with the next big rally scheduled for Saturday, December 24.