People vote for parliamentary election at a polling station in Moscow
Vladimir Putin's ruling party suffered a surprise drop in support in legislative elections Sunday seen as a crucial test of the Russian strongman's popularity ahead of his planned return to the Kremlin, exit polls said.
United Russia was on course to win but with less than half the vote, two exit polls showed, after an election marred by allegations the authorities had committed major violations to ensure the party hung on to its dominance, reports AFP.
The party was to win 48.5 percent of the vote, ahead of its nearest rival the Communist Party with 19.8 percent, according to the poll by the All-Russian Public Opinion Research Centre (VTsIOM) broadcast on state television.
The poll said the opposition A Just Russia party would win 12.8 percent and the ultra-nationalist Liberal Democratic Party 11.4 percent, with liberal parties not polling enough to make parliament.
A second exit poll by the Foundation for Public Opinion (FOM) predicted that United Russia would receive 46 percent and the Communist Party 21 percent, state television said.
The result would be a setback for United Russia and Putin after in the last parliamentary elections in 2007 United Russia secured a landslide majority of 64.3 percent and won 315 seats in the 450 seat State Duma.
Nevertheless, United Russia chairman, Boris Gryzlov congratulated the party faithful for their "victory".
The Communists complained the elections were hit by "mass fraud" that turned them into a "war zone".
The four years since the last parliamentary vote have been marked by an outburst of criticism of the authorities on the Internet as web penetration of Russia started to finally catch up with the rest of Europe.
Putin was recently subjected to unprecedented booing when he made an appearance at a martial arts fight and opinion polls have shown chinks in his once impregnable popularity.
The elections are seen as a crucial test of Putin's popularity in Russia as he prepares to stand in March 2012 presidential elections to return to the Kremlin after his four-year stint as prime minister.
Opponents said the vote was marred by unprecedented violations as the ruling elite had downed websites and harassed monitors to limit dissent.
Independent monitor group Golos (Voice), which claimed rampant violations in the campaign, said its "Map of Violations" website documenting reports of fraud was inaccessible due a cyber-attack and its email was paralysed.
But it still was working via Skype and telephone, noting violations like the failure of the Volga city of Samara to allow observers inside to inspect ballot boxes before polls opened.
"Those people who wanted to stop us have not succeeded," said Arkady Lyubarev, the head of election monitoring at Golos.
The website of popular radio station Moscow Echo, which is owned by state gas monopoly Gazprom but often tackles sensitive issues, was the subject of a similar distributed denial of service (DDoS) attack.
"The attack on the website on election day is clearly an attempt to inhibit the publication of information about violations," Moscow Echo editor-in-chief Alexei Venediktov wrote on Twitter.
Putin had lashed out at Golos last weekend, suggesting its activity was tantamount to a betrayal of Russia. President Dmitry Medvedev Friday rejected claims of foul play saying elections were "one of the greatest manifestations of democracy".
Russia's two rulers -- who are set to swap jobs in 2012 with Medvedev becoming prime minister -- voted at separate Moscow polling stations looking confident but without making comment.
The marathon election process in the world's largest country kicked off in Pacific Ocean regions and concluded 21 hours later when polls closed in the exclave of Kaliningrad bordering the European Union, nine time zones away.
Turnout will also be closely watched to see how many Russians are disillusioned with the political process after more than a decade of Putin's strongman rule.
According to information received by 1500 GMT, almost 50.4 percent of the electorate had voted, the election commission said.
Police detained around 100 protesters including radical opposition leader Eduard Limonov for holding an unsanctioned protest in Moscow, while another 70 were held at a similar event in Saint Petersburg, police in the two cities said.