Putin, who has been in power as president or prime minister for nearly two decades, urged the Russian populace to vote.
"The only source of power is the people," Putin said in comments published on the Kremlin website Friday.
Polls opened at 8 A.M. local time Sunday in Russia's Far East regions of Chukotka and Kamchatka. Voting will conclude at 8 P.M. in Kaliningrad, the Baltic exclave that is Russia's westernmost region. Russia is the largest country in the world and stretches across 11 time zones.
Putin has maintained approval ratings of around 70 percent in recent years, according to nationwide surveys by the country's two largest pollsters – one state-run and the other independent.
The length of Putin's rule, however, has prompted speculation that many potential voters might abstain in an election whose result appeared largely predictable.
One of Putin's fiercest critics, protest leader Alexei Navalny, has been barred from running in the election because of a financial crimes conviction that he attests was trumped up.
Navalny has called on Russians to boycott the election and expressed hope that it would be undermined by low voter turnout.
Putin's three main challengers, according to the polls, were the Communist Party's Pavel Grudinin, nationalist firebrand Vladimir Zhirinovsky and socialite-turned-journalist Ksenia Sobchak.
A nationwide poll last week by the state's largest pollster, the Russian Public Opinion Research Centre, showed that 69 percent of the respondents would vote for Putin.
Grudinin came in a distant second in that poll with 7 percent, followed by Zhirinovsky with 5 percent and Sobchak with 2 percent.
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