Update 10.30pm: Vladimir Putin has won a fourth term as Russia's president, adding six years in the Kremlin for the man who has led the world's largest country for all of the 21st Century.
Mr Putin addressed thousands of people who rallied outside the Kremlin tonight to thank them for their support and promised new achievements.
Speaking to a crowd who attended a pop concert marking his election victory, Mr Putin hailed those who voted for him as a "big national team", adding that "we are bound for success".
He said that the nation needs unity to move forward and urged the audience to "think about the future of our great motherland".
He then led the enthusiastic crowd to chant "Russia!"
Results from more than half of precincts showed Putin winning over 75% of the vote, with Communist candidate Pavel Grudinin and ultra-nationalist Vladimir Zhirinovsky trailing far behind with about 13 and 6%, respectively.
The vote was tainted by widespread reports of ballot-box stuffing and forced voting, but the complaints will likely do little to undermine Mr Putin.
Earlier: Early returns suggest 72% majority for Putin in Russian election
Update 8.30pm: Vladimir Putin looks set to be Russia's president for another six years as an exit poll and early returns suggest he has easily won a fourth term.
The vote was tainted by widespread reports of ballot-box stuffing and forced voting, but the complaints are likely to do little to undermine Mr Putin.
The Russian leader's popularity remains high despite his suppression of dissent and reproach from the West over Russia's increasingly aggressive stance in world affairs and alleged interference in the 2016 US election.
Mr Putin's main challenges in the vote were to obtain a huge margin of victory in order to claim an indisputable mandate. The Central Elections Commission said he won about 72% of the vote, based on a count of 22% of the country's precincts.
Russian authorities sought to ensure a large turnout to bolster the image that Mr Putin's so-called "managed democracy" is robust and offers Russians true choices.
He faced seven minor candidates on the ballot. His most vehement and visible foe, anti-corruption campaigner Alexei Navalny, was rejected as a candidate because he was convicted of fraud in a case widely regarded as politically motivated.
Earlier: Officials report 51.9% turnout in Russian election
Russia's Central Election Commission has reported more than 50% turnout in the presidential election in which President Vladimir Putin is certain to win another six years in office.
Mr Putin faces seven challengers, but none poses a serious threat.
The commission said 51.9% of Russia's nearly 111 million eligible voters have cast ballots.
Election officials said efforts to encourage a higher turnout are in line with the law. Some Russians have reported being pressured by employers to show up and vote.
Election commission chief Ella Pamfilova also said officials around the country are taking quick measures in response to claims of violations.
Independent election observers and activists have alleged numerous incidents of ballot stuffing and other irregularities in today's vote.
The commission said it is quickly responding to claims of violations in the vote.
Commission chief Ella Pamfilova said: "We are immediately reacting to all claims, no matter where they come from."
She said officials quickly sealed a ballot box in the southern city of Rostov-on-Don where ballot stuffing was reported.
Election officials have responded similarly to allegations of ballot stuffing in the town of Lyubertsy just outside Moscow and the far eastern town of Artyom and have been looking into several other complaints.
In Artyom, a man tossed several ballots into the box, according to Tatiana Gladkhikh, the head of the regional election commission. She said the ballot box was sealed and the man was arrested.
Russian opposition leader Alexei Navalny says he boycotted the presidential election and advises other Russians to do the same.
Mr Navalny was barred from the campaign because of a criminal conviction widely seen as politically motivated. He urged his supporters not to vote because of the absence of any real competition in today's election.
Mr Navalny said in a video posted on YouTube that "on election day, one should usually want to say 'I voted', but in fact I'm here to say that I didn't go to vote."
He criticised the seven contenders challenging Mr Putin for failing to protest against ballot stuffing and other irregularities tainting the election, saying on his blog that "such candidates aren't worthy of your vote."
Russian opposition presidential candidate Ksenia Sobchak cast her ballot and urged Vladimir Putin's critics to vote instead of boycotting.
Ms Sobchak, a 36-year-old former TV star, told reporters in Moscow that the higher the support for Mr Putin in the vote, "the tougher the system" Russians will face in his new term.
Ms Sobchak urged Mr Putin's critics to "come together", and argued against the boycott called for by opposition leader Alexei Navalny, who is barred from running.
She said "every extra percentage point" for Mr Putin is a result of those who refuse or do not bother to vote.
Critics think Mr Sobchak has the tacit support of the Kremlin so that the election looks more democratic, which she denies. She is the only candidate who has openly criticised Mr Putin in the campaign.
Russia's central election commission says its website was the target of an unsuccessful hacking attempt during Sunday's presidential election.
Commission chairwoman Ella Pamfilova said it was a DDoS, or distributed denial of service, attempt tracked to computers in 15 countries, without naming them. Such attacks are very common.
She said efforts to disrupt the site occurred when voters in Russia's far east were already casting ballots, but they were deterred by Russian authorities.
As US authorities investigate alleged Russian hacking and other interference in President Donald Trump's 2016 election, Russian authorities claimed that foreign powers are seeking to interfere in Sunday's vote.
Mr Putin hopes for high turnout despite widespread apathy.
Some 145,000 observers are monitoring the voting in the world's largest country, including 1,500 foreigners and representatives from Mr Navalny's political movement.
Security forces have been surrounding Russian facilities in Ukraine amid anger over the Ukrainian government's refusal to allow ordinary Russians to vote for president.
Ukrainian police are guarding the Russian Embassy in Kiev and consular offices in Odessa and other cities and the Ukrainian government said only Russian diplomatic officials would be allowed to cast votes.
Millions of ethnic Russians live in Ukraine but the number of registered Russian voters in Ukraine is unclear.
Ukraine is protesting against voting in Crimea, annexed by Russia from Ukraine four years ago, and is angry over Russian support for separatists in eastern Ukraine, where a deadly conflict continues.
Russian authorities are appealing to the United Nations and Council of Europe to intervene, according to Russian news agencies.