Up to 300 Russians have been arrested in Moscow after a series of protests against the result of a parliamentary election hit by accusations of fraud.
Thousands of people took to the streets on Monday in what were Russia's largest protests in years, after foreign monitors claimed that box-stuffing, cyber-attacks and harassment of officials had invalidated the result of the poll.
Up to 10,000 demonstrators gathered in the Chistye Prudy area of Moscow to protest the election, and attempted to march on the Central Elections Commission near the Kremlin.
They chanted "Revolution!" and "Russia without Putin" and held banners attacking Prime Minister Vladimir Putin's ruling 'United Russia' party.
"Down with the Party of Swindlers and Thieves!" some of the banners read.
Many activists were detained in buses and taken away to cells before the protests reached the commission.
In another demonstration 400 members of the Communist party, which came second in Sunday's elections, also protested the result. Protests were also staged in St Petersburg where 100 people were arrested.
Prime Minister Vladimir Putin's ruling 'United Russia' party won 238 seats in the 450-seat State Duma in the election, which was less than the 315 it won in 2007.
However observers and foreign politicians have claimed that Putin would have suffered even greater loses had the elections been held under fair conditions.
"We do have serious concerns about the conduct of the elections. We think that the preliminary report just issued by the OSCE international mission raised a number of questions about the conduct of the elections," said US Secretary of State Hillary Clinton.
"To me, this election was like a game in which only some players are allowed to compete," Heidi Tagliavini, head of the observation mission for the Organisation for Security and Cooperation in Europe told The Wall Street Journal. "And the game was tilted in favor of one of the players."