Updated

A Russian court will on Thursday deliver a verdict in the embezzlement trial of top protest leader Alexei Navalny, an abrasive critic of President Vladimir Putin who risks years in prison and an end to his budding political career.

Navalny, 37, who emerged as a powerful new political force in mass protests against Putin that broke out in December 2011, dismisses charges he colluded to steal money in a timber deal while acting as an unpaid advisor to the governor in the northern Kirov region.

Prosecutors in the regional capital of Kirov are seeking a six-year prison colony sentence, but any conviction would disqualify Navalny from politics.

Navalny bluntly predicted on his blog Wednesday that he would be found guilty, and that Putin would be behind the decision.

Putin would either "wimp out" and order a suspended sentence or "get up the courage and it will be a jail term", he wrote.

The verdict comes a day after Navalny was accepted as a candidate for the high-profile Moscow mayoral race in September, raising the bizarre prospect that he could run for office while already behind bars.

Navalny's disqualification from politics would only take effect after the appeals process is exhausted, so he could still theoretically campaign during this period.

The trial is seen by the opposition as part of a wider crackdown on activists who took to the streets to demand an end to Putin's rule in the run-up to his return to the Kremlin in May 2012 for a third term.

Many have spent months in cells awaiting trial and face long jail terms for crowd violence.

Ahead of the trial in Kirov, a sleepy city 600 kilometres (370 miles) from Moscow, young supporters handed out leaflets on the main square urging passers-by to come to the court to back "Putin's number one enemy."

International journalists swarmed the city to jostle for the courtroom's 60 seats to hear judge Sergei Blinov's ruling.

Navalny has eloquently defended himself in the hurried trial, which began in April. Judge Blinov, who has never acquitted anyone in his career, has listened largely silently, sometimes taking notes.

The trial has given little explanation for the alleged embezzlement, given Navalny's apparently humdrum lifestyle in a small flat in a Moscow suburb with his wife Yulia and two children.

Supporters in Kirov were downbeat ahead of the verdict, even as Navalny's selection as mayoral candidate raised hopes of a last-minute reprieve from the authorities.

"I'd like to believe that they have a cunning plan, but they are not cunning: they have chosen the option of force," said supporter Nikolai Lyaskin who travelled from Moscow for the trial.

With his streetwise rhetoric and charisma, Navalny emerged as the most effective of the opposition leaders who led the unprecedented protests against Putin.

Navalny has said he wants to challenge Putin in the next presidential elections in 2018 and coined the phrase "party of crooks and thieves" to describe the ruling United Russia party.

In a typically uncompromising gesture, Navalny this week published a detailed report accusing one of Putin's closest allies, the head of Russian Railways, Vladimir Yakunin, of possessing vast undeclared property and business assets.

But some within the opposition have criticised Navalny, saying he lacks a clear vision for the country beyond cracking down on corruption and bluntly vowing to jail opponents should he win power.

Navalny has also yet to win wide recognition beyond his powerbase in Moscow, where he has become a hero for many in the Internet-savvy middle class who yearn to live in a different Russia.