We have seen a man who wasn't sure of himself

Riot police have broken up an opposition protest contesting Prime Minister Vladimir Putin's victory in Russia's presidential election, arresting dozens of participants, including prominent opposition leaders.

The police action followed a rally in central Moscow on Monday that drew about 20,000 protesters angry over a campaign christian louboutin slanted in Putin's favour and reports of widespread violations in Sunday's ballot.

The big rally went on peacefully, but hundreds of police in full riot gear violently dispersed several hundred protesters who had vowed to stay on the iconic Pushkin Square until Putin steps down.

Police moved quickly to disrupt the protests, apparently fearing that it could act as a catalyst for bigger opposition action.

Charismatic protest leader Alexei Navalny, who sought to electrify the crowd with a passionate call of "We are the power!" was among those arrested, along with opposition leader Sergei Udaltsov. Scores were put in police vans parked around the square.

Putin won more than 63 per cent of the vote, according to the nearly complete official returns, but the opposition says the election was marred by massive fraud.

The campaign has been unfair, cowardly and treacherous," said opposition leader Grigory Yavlinsky, who had been denied registration for the race on a technicality.

International election monitors pointed at the lack of real competition and said the vote count "was assessed negatively" in almost a third of polling stations observers visited.

"There was no real competition, and abuse of government resources ensured that the ultimate winner of the election was never in doubt," said Tonino Picula, the head of the short-term Organisation for Security and Cooperation in Europe observer mission.

"Broadcast media was clearly biased in favour of one candidate and did not provide fair coverage of the other candidates."

Russian observers pointed at numerous reports of "carousel voting", in which busloads of voters are driven around to cast ballots multiple times and various other violations, saying their number appeared to be as high as in December's disputed parliamentary vote that kicked off the protests.

Monday's rally was been sanctioned by authorities but security was tight, with some 12,000 police deployed to ensure order.

About 100 protesters were also arrested in St Petersburg, where about 2000 gathered for an unauthorised rally.

The independent Russian elections Christian Louboutin Evening watchdog Golos said incomplete reports from its observers of individual polling station counts contradicted the official vote count, indicating Putin hovered perilously close to the 50 per cent mark needed for a first-round victory.

"It's one pixel away from a second round," said Golos' Roman Udot.

Putin claimed victory on Sunday night when fewer than a quarter of the votes had been counted, his eyes brimming with tears. He defiantly proclaimed just outside the Kremlin walls before a sea of supporters that they had triumphed over opponents intent on "destroying Russia's statehood and usurping power".

The protesters on Monday derided Putin's tears as an evidence of his fear of the opposition.

"We have seen a man who wasn't sure of himself," said Ilya Yashin, one of the opposition leaders.

In an apparent bid to assuage the opposition anger, outgoing President Dmitry Medvedev told the Justice Ministry to present its explanation for last year's rejection of registration for the People's Freedom Party, an organisation led by some of the opposition's most prominent figures.

He also ordered the prosecutor-general to re-examine the legality of the conviction of imprisoned former oil tycoon Mikhail Khodorkovsky and more than 30 others regarded by the opposition as political prisoners, in an apparent attempt to soothe protesters.

The West can expect Putin to Christian Louboutin Stretch Platform OTK Boot continue the tough policies he has pursued even as prime minister, including opposing US plans to build a missile shield in Europe and resisting international military intervention in Syria.