MOSCOW (AFP) - Russia has suddenly brought forward the verdict on top anti-Kremlin figure Alexei Navalny's fraud trial to Tuesday after thousands of his supporters pledged to take to the streets next month, his lawyers said.

"The announcement of the verdict will take place tomorrow, Dec 30 at 9am," Navalny wrote in his blog on Monday.

A Moscow court had previously been expected to deliver its verdict on Jan 15.

This month prosecutors called for Navalny to be sentenced to 10 years in prison.

Analysts expressed concern that his chances of avoiding jail appeared slim.

"I am not aware of a single case when the announcement of a verdict was brought forward," Navalny's lawyer, Ms Olga Mikhailova, told AFP.

Navalny's team said the move was aimed at pulling the rug from under the feet of thousands of his supporters, who had pledged to turn up near the Kremlin walls on Jan 15.

The move caps a turbulent year that has seen the Kremlin lock horns with the West over Ukraine and ramp up pressure against the opposition at home amid brewing economic trouble.

"There are no exceptions that cannot be arranged for good people," Navalny, who has been under house arrest since February, said wryly on his blog.

His spokesman, Ms Kira Yarmysh, said the authorities violated existing procedures by re-scheduling the day of the ruling.

Speaking on radio, she added that Navalny had learnt of the decision from prison officials who called a special telephone line installed in his apartment.

The reading of the verdict can take more than a day.

'CHANCES GROW OF JAIL'

Analysts had warned that the crackdown on Navalny could backfire amid mounting economic woes.

Some had said the January rally threatened to become the biggest demonstration against President Vladimir Putin's rule since the beginning of Moscow's confrontation with the West over Ukraine last year.

Navalny, who shot to prominence during anti-Kremlin protests in 2011-2012 which have since fizzled out under a crackdown, already faced a five-year term over embezzlement last year but walked away with a suspended sentence to general astonishment.

Along with his brother Oleg, Navalny is now accused of defrauding French cosmetics company Yves Rocher of nearly 27 million roubles (more than half a million dollars at the exchange rate at the time).

The French firm has said that it suffered no damages.

More than 30,000 people had pledged to attend the Jan 15 rally.

Navalny's supporters swiftly regrouped, calling for a new rally on Tuesday.

"They got scared of a popular gathering on January 15," they said on Facebook, referring to authorities.

About 13,000 had pledged to attend the Tuesday rally by late Monday.

Political analyst Alexei Makarkin said the move indicated that Navalny could be jailed rather than getting a suspended sentence.

He added that authorities risked triggering clashes because many Muscovites chose to stay at home instead of seeing in the New Year abroad because of the financial crisis.

Mr Nikolai Petrov of the Higher School of Economics struck a similar note. "I am afraid that Navalny will get a real prison term."

Navalny has said he believes Mr Putin will personally decide his fate.

Navalny's influence increased after he came second in the Moscow mayoral election last year, polling more than 27 per cent of the vote.

'VERDICTS HAVE BEEN PREPARED'

The sudden announcement ignited the Russian Twittersphere.

MID Roissi, a satirical Twitter account that parodies the Russian foreign ministry feed, posted a picture of a smiling Putin raising a salutary glass of champagne.

The gag, re-tweeted by Navalny, said: "Dear Russians, your verdicts have already been prepared. It's just not all of you know about it yet."

The sudden decision to bring forth the verdict is reminiscent of the end of 2010 when a judge raced against time to wrap up a second trial of Kremlin critic Mikhail Khodorkovsky by the New Year.

On Dec 30, 2010, Mr Khodorkovsky was sentenced to a second term in prison over theft and money-laundering. Last December, Mr Putin suddenly pardoned Mr Khodorkovsky after a decade in prison.

Polls shows that most Russians support Mr Putin, while a minority disagrees with his policies, claiming the country is hurtling towards political and economic catastrophe.