Riot police beat dozens and detained hundreds of activists at anti-government protests this month in Moscow and St. Petersburg, prompting harsh criticism from human rights groups and some Western governments.
The police actions reinforced opposition contentions that President Vladimir Putin's government is curtailing democracy and suppressing dissent before December parliamentary elections and a presidential vote in March.
The State Duma, the Russian parliament's lower house, is investigating the protesters' actions "to determine the organizers and sponsors of those events," said Yuri Bosenko, an aide to deputy Duma Speaker Oleg Morozov. Some officials have previously suggested that foreign governments were interested in destabilizing Russia and were funding street protests and opposition groups.
Meanwhile, the Public Chamber, a government-created oversight agency, has begun its own investigation into widespread accusations that riot police unlawfully used force to break up the rallies, agency spokeswoman Maria Ryklyna said.
The agency decided to request a meeting with senior law enforcement officials after hearing complaints about police actions from Russia's leading rights activists on Tuesday, she said.
Interior Ministry spokesman Valery Gribakin said last week that the actions of law enforcement officials were being "thoroughly studied and analyzed," but added that the same was true for the protesters and contended that police were provoked.
Meanwhile, Ekho Mosvky radio reported Tuesday that riot police had beaten another group of demonstrators on Sunday after they held a small protest against the removal of World War II graves from a location just outside Moscow.
"I have never seen such brutal treatment," witness Nadezhda Khoroshilova told the station. "They kicked (them) with their feet. They hit one girl so hard that she lost consciousness. They punched them in the back ... the stomach, the face."
Moscow police officials could not be immediately reached for comment.