Russian Prime Minister Vladimir Putin has accused the United States of inciting unrest following the country's parliamentary election.
Mr Putin says criticism of the poll by US secretary of state Hillary Clinton has encouraged government opponents to protest.
He says Mrs Clinton set the tone for some opposition activists, who were involved in three days of demonstrations following the election.
Russian President Dimitry Medvedev has, however, acknowledged there may have been irregularities in the poll.
On a visit to the Czech Republic, Mr Medvedev conceeded there was evidence of shortcomings in the election, in which his United Russia party won a majority, the BBC reports.
The majority was reduced from the previous election.
Mr Medvedev says the shortcomings should be thoroughly examined by experts and the courts.
He says the demonstrations that followed the vote were a reflection of democracy.
Another protest is being organised for this weekend.
