United Russia, backed by President Vladimir Putin, clinched majority in the country's parliamentary election, far ahead of rival parties.
With 93 per cent of the votes counted, the party secured 54.2 per cent of ballots and 343 seats in the 450-member parliament, election commission officials said, reports BBC.
Putin said his party achieved a very good result; however the turnout was a record low of 47.8 per cent.
The Communist Party and nationalist LDPR both secured just over 13 per cent.
The party A Just Russia gained just over 6 per cent of the votes. All four parties are loyal to Putin and dominated the last parliament, or State Duma.
Putin has enjoyed 17 years in power as either president or prime minister.
Voting irregularities were reported in several areas and the head of the election commission suggested that the results might be cancelled in three polling stations.
Liberal opposition parties failed to get enough votes for party-list representation. "To my utmost regret, not one other party managed to get over the 5 per cent barrier," said Central Election Commission head Ella Pamfilova.
The two main opposition parties allowed to field candidates, Yabloko and Parnas, received just 1.89 per cent and 0.7 per cent respectively.
Half the seats were also being contested in constituencies but even there the small number of opposition candidates failed to win.
The result increases United Russia's majority, after it achieved 49 per cent of the vote in the 2011 Duma elections. The party, led by Prime Minister Dmitry Medvedev, will take more seats in parliament, up from 238.
However, the turnout, based on partial figures, was the lowest in Russia's modern history and significantly down on the 60 per cent turnout in 2011.
Election commission head Ella Pamfilova, a respected human rights activist, said she was fully confident that the elections are proceeding in a quite legitimate way. But later she warned that results at three polling stations might be cancelled because of irregularities.
There were reports of serious irregularities in one Siberian region, with suggestions of "carousel" voting - people bussed around polling stations - in the city of Barnaul.
In the Caucasus, youths smashed up a polling station in the Khunzakh district of Dagestan, accusing officials of stuffing ballots to favour one candidate, Pamfilova said.
And in the southern region of Rostov a criminal case was opened for alleged electoral fraud, she said.
Some voters unhappy with the election posted pictures of their spoiled ballots on Twitter and Instagram. Some of them mockingly voted for "Pikachu" - fictional creatures from the hugely popular Pokemon Go game.
For the first time, people voted in Crimea, annexed from Ukraine in 2014 in a move condemned internationally. United Russia won all the region's constituency seats, in a vote that prompted protests in the Ukrainian capital, Kiev.
Chechnya's leader Ramzan Kadyrov - a firm ally of Putin who runs his troubled North Caucasus republic with an iron fist - swept to victory with 98 per cent support, with 78 per cent of votes counted.
Vote-rigging sparked big anti-government street protests after Russia's last parliamentary election in 2011.
In the system of "managed democracy" crafted by the Kremlin, it was unthinkable that President Putin's control of parliament would be weakened, news media report from Moscow.
Putin will be hoping that this time his personal popularity, combined with widespread apathy, will mean that Russians accept the result, he said.
The independent election monitoring group Golos said that although the level of violations in this election campaign was lower than in 2011 there were many in the run-up to the voting.
It said the elections were far from what could be called really free and fair. The number of independent observers at polling stations was lower than before, and there were cases of ballot-stuffing, carousel voting and other abuses, Golos complained.
Russian papers see the result largely as a vote of confidence in President Putin - and as pretty much predictable.
"The election is primarily an informal referendum on trust in the person who is in charge of making all the key decisions," tabloid Moskovsky Komsomolets declares.
The news website Gazeta.ru said the vote brought no sensations, while the influential business daily Kommersant's editorial is simply headlined: "The party of power is in power again".
Russian state Rossiya 24 TV mentioned allegations of election were fraud, but said they were not significant and were being investigated.
But business daily Vedomosti says that - despite the authorities' promises - the election "was not a model of honesty". –RH