Opponents accused Russian authorities of mass fraud on Monday after the ruling United Russia party, which supports President Vladimir Putin, won a bigger than expected parliamentary majority despite unease over living standards.
With over 99% of ballots counted, the Central Election Commission said United Russia had won nearly 50% of the vote, with its nearest rival, the Communist Party, taking just under 19%.
The scale of the victory means United Russia will have more than two-thirds of deputies in the 450-seat State Duma lower house of parliament. This will enable it to continue to push through laws without having to rely on other parties.
United Russia, a party that Putin helped found, had always been expected to win. Its most vociferous critics, allies of jailed Kremlin critic Alexei Navalny, were prevented from taking part after a court branded them extremists in June.
Putin gave a short statement, thanking voters after the Kremlin had hailed the result, saying United Russia had confirmed its role as the leading party. The Kremlin said the election had been competitive, open and honest.