Vladimir Putin tears up as he addresses supporters during a rally near the Kremlin in Moscow on Sunday night. [Xinhua News Agency]

Vladimir Putin has been declared Russia's first three-term president after a landslide victory in Sunday's polls, as the celebratory mood of his supporters collided with protests on Monday night in the heart of the Russian capital.

The current Russian prime minister secured 63.71 percent, or 44.9 million votes, after 99.5 percent of all ballots had been counted, overwhelming the other four candidates, with Communist leader Gennady Zyuganov, the closest contender, winning just 17.19 percent.

"According to preliminary data, Vladimir Vladimirovich Putin has been elected president of Russia," Vladimir Churov, head of Russia's Central Election Committee, announced during a news briefing in Moscow on Monday morning.

Independent candidate Mikhail Prokhorov, the only fresh face in the elections, finished third with 7.86 percent. Vladimir Zhirinovsky of the Liberal Democratic Party of Russia and Sergei Mironov of A Just Russia received 6.23 percent and 3.85 percent of the vote, respectively.

In Moscow, Putin's campaign chief Stanislav Govorukhin said the elections were the cleanest in Russian history, while Zyuganov said he "cannot recognize" the event as "fair, honest and worthy". Prokhorov too said he did not consider the elections fair, contending that he "deliberately agreed to play by somebody else's rules".

Churov quickly dismissed these allegations and said the elections were competitive. "It was very competitive from my side, from the side of the chair of the Central Election Commission," he told China Daily on Monday.

The voters were "highly active", and there was a high degree of competition between candidates prior to the election, he said.

Ewald Stadler, a member of the European Parliament and an international observer, said Russia had made great developments in democracy and the election procedures were "really fair".

Some 70,000 Putin supporters on Sunday night gathered for a two-hour celebration at Manezh Square, just outside the Kremlin, as poll results were released. The event, a mixture of pop songs and speeches, culminated with Putin's appearance on stage.

"We won in an open and honest fight!" an uncharacteristically emotional Putin, with outgoing President Dmitry Medvedev by his side, told the crowd as his voice cracked and eyes moistened.

"I told you we would win and we won!" he said, urging everyone "to unite around the interests of Russia".

The strongman's first-round victory was widely anticipated, as were the opposition's allegations that the elections were rigged.

The Sunday elections came months after mass protests against allegations of vote fraud in favor of the ruling United Russia party in parliamentary polls in December. Putin himself earlier said the protests - which were scheduled at Pushkinskaya Square, near the Kremlin, on Monday night - were to be expected one way or the other. Prokhorov, whose campaign Putin endorsed as "dignified and interesting", had said he would attend the rally.

Film director Nikita Mikhalkov hailed Putin's success in the early celebrations on Sunday night, saying: "The part of the opposition that does not listen to anything and tries to declare the elections illegitimate doesn't interest Putin."

Meanwhile, Grigory Fyodorov, first deputy secretary of the Russian Public Chamber, said the validity of the election is clear to everyone, including the opposition. "Even if we sum up all violations which took place - and they, naturally, did - this won't affect the existing results in any way," he said.

"Putin was to win in the first round, he is just more popular. Figures are figures."