Russia's Communist Party on Saturday led a thousand-strong protest in central Moscow over what they called "colossal" fraud in parliamentary polls as police detained a number of activists.

It was the first sizable Moscow protest since this month's controversial polls, and police did not break up the unsanctioned rally but played loud music in an effort to drown out the protesters.

Before and during the protest, authorities detained a number of activists including Sergei Udaltsov, head of a radical socialist group, Left Front, according to OVD-Info, which tracks detentions at opposition rallies.

Many Russians in Moscow and elsewhere backed the Communists as a form of protest voting
Many Russians in Moscow and elsewhere backed the Communists as a form of protest voting AFP / Yuri KADOBNOV

In his residence outside Moscow, President Vladimir Putin hailed the ruling party's "convincing victory" and said Russian democracy was growing stronger as he hosted the heads of five parties which won parliamentary seats including Communist leader Gennady Zyuganov.

Putin opponents have accused the authorities of mass fraud after results showed the deeply unpopular ruling United Russia party winning a sweeping majority in parliament at legislative polls.

The three-day vote took place following a historic crackdown on the opposition, with authorities imprisoning Putin's most vocal critic Alexei Navalny and formally outlawing his organisations.

Thirty years after the collapse of the Soviet Union, many Russians in Moscow and elsewhere backed the Communists as a form of protest voting, some for the first time.

IMAGES Thousands of people gather in Moscow for a demonstration called by the Russian Communist Party, to protest against the results of the parliamentary elections. The Russian opposition denounced massive fraud in the elections which saw the Kremlin par
IMAGES Thousands of people gather in Moscow for a demonstration called by the Russian Communist Party, to protest against the results of the parliamentary elections. The Russian opposition denounced massive fraud in the elections which saw the Kremlin party win a two-thirds super-majority, the end of a tailor-made ballot from which Vladimir Putin's critics had been excluded. AFPTV / Andrey BORODULIN

More than a thousand protesters packed Pushkin Square on Saturday as Communist figures decried what they called a stolen election, an AFP correspondent said.

The crowd chanted "Putin is a thief!" and called for the release of political prisoners.

Some protesters carried signs demanding a recount, others expressed support for Navalny.

Some protesters at the rally said they did not support Communism as a political ideology but showed up at the protest anyway to express their anger over electoral fraud.

Opponents of President Vladimir Putin have accused the authorities of electoral fraud
Opponents of President Vladimir Putin have accused the authorities of electoral fraud AFP / Yuri KADOBNOV

"Not only members of the Communist Party are here," Deniza Lisova, 26, told AFP.

"Everyone is here, and we all supported the Communist Party during the election."

Members of the Communist Party took particular issue with electronic voting results in Moscow which reversed Communist Party candidates' strong leads during the September 17-19 vote.

"United Russia has stolen lawmaker mandates," Valery Rashkin, first secretary of the Communist Party in Moscow, told protesters.

"There's been colossal voter fraud in Moscow," Rashkin said, adding the party would contest the election results.

Protester Ruslan Karpov struck a similar note.

"I do not believe the online voting was honest because it is unclear who voted for whom, it's impossible to control it," said the 29-year-old.

Some top Navalny associates praised the rally, with Lyubov Sobol calling them "cool" on Twitter.

On Monday, the Communist Party led a smaller protest that saw a few hundred people gather in Moscow. Police detained a number of party members and activists afterwards.

Speaking to the party leaders on Saturday, Putin pointed out that for the first time since 1999 parliament's lower house would have five factions instead of four, hailing it as a sign of "the democratic development in our country."