MOSCOW - President Vladimir Putin's party won a large majority in Russia's election on Sunday, but opposition parties cried foul and vowed to contest results which the Kremlin hailed as a big endorsement for Putin.

First official results showed United Russia winning over 60 percent of the vote -- an outcome likely to be seen by the Kremlin as a strong mandate for Putin to maintain a position of influence after his final presidential term ends next year.

"The overwhelming majority of Russian voters spoke in favour of United Russia, thus supporting President Putin's course, and spoke in favour of it being continued after the current president's second term ends," a Kremlin spokesman, Dmitry Peskov, told Reuters after early results came in.

Election monitors reported widespread cases of ballot fraud, and the Communist Party, which is likely to be the biggest opposition force in the next parliament, said it would contest the election in the courts.

"These results are not fair. We intend to challenge them in the Supreme Court," said Communist leader Gennady Zyuganov.

Boris Nemtsov, whose small Union of Right-wing Forces opposition party fell short of the 7-percent hurdle needed to qualify for seats in parliament, was more outspoken.

"I have been in politics for 20 years and these are the most dishonest elections in the history of modern Russia. Putin won with the help of cynicism (and) lies," he said.

But head of the Central Election Commission, Vladimir Churov, a former colleague of Putin who was appointed election chief this year, dismissed the opposition allegations.

"I think there were no serious violations on polling day. At least during the voting not one party leader called me and no-one complained (to me)," Churov said.

With 30.4 percent of votes counted, United Russia had 63.3 percent of the vote, with nearest rivals the Communists on 11.3 percent, Churov told reporters.

Two other parties -- both of which have a record of backing the Kremlin -- will make it into parliament, he said.

An exit poll from state-owned pollster VTSIOM gave a similar picture, with Putin's party on 61 percent and the same four parties in parliament.

A "NATIONAL LEADER"

According to VTSIOM's calculations, that vote would give pro-Kremlin parties 348 seats in parliament -- far more than the 301 needed to change the constitution. This was something analysts say was a key Kremlin target in the election.

This could allow Putin to change the constitution to give himself a third straight term -- something he has ruled out -- or to enhance the power of whichever role he takes after he steps down.

Putin said before the election a big vote for his party would give him a "moral right" to mould policy after he leaves the presidency next year. But he has not said what role he will take or whom he favours to succeed him as presidency.

Chris Weafer, chief strategist at Uralsib investment bank in Moscow, said the results were "not spectacular but good enough to allow President Putin to call the shots after March".

"He now has the initiative in terms of what role he wants to stay on in", said Weafer. United Russia fell short of Putin's personal vote of 71.3 percent in the 2004 presidential election.

Even before polls closed, opposition parties cried foul, alleging that numerous instances of pressure on voters, a one-sided campaign and systematic electoral fraud undermined the legitimacy of the result.

"These are not isolated incidents. The complaints are from every corner of Russia," said Grigory Melkonyans of Golos, Russia's biggest independent election observer.

But Putin's popularity contributed to his party's strong showing. Russians credit him with overseeing an oil-fuelled economic boom and like his no-nonsense approach -- including a military build-up and verbal attacks on the West -- that has restored national pride.

In the Siberian village of Belovsky, local election officials brought a ballot box to the home of 94-year-old Sofia Kolesnikova because she was too frail to go out.

"My legs don't move, but my head works," she said. "Today I voted for Putin and for United Russia, because our president supports the young ... And what's more, as a man, how I like him!"

The West's main election monitoring body, the ODIHR, did not monitor Sunday's poll after a row with Moscow over delays in issuing visas for observers.

A reduced group of international observers was to give its verdict on the vote on Monday. A U.S. State Department spokesman said it would have no comment until official results are in.