KIROV, Russia — Russian state prosecutors demanded a six-year jail sentence on Friday for protest leader Alexei Navalny, one of President Vladimir Putin's biggest critics, on charges of theft.

Although prosecutor Sergei Bogdanov did not seek the maximum 10-year term possible at the trial in the industrial city of Kirov, a six-year sentence would keep Navalny in prison until after the next presidential election in 2018.

Navalny denies charges of stealing 16 million rubles ($482,000) from a local timber firm that he was advising in 2009 while working for the liberal regional governor, and says they are intended to sideline him as a potential rival to Putin.

"I ask the court to find Alexei Navalny guilty . . . and sentence him to six years in prison and a fine of 1 million rubles," Bogdanov told the court in Kirov, 550 km (900 miles) northeast of Moscow.

Looking shocked, Navalny, 37, exchanged nervous smiles with his wife Yulia. She then embraced him when a short break in proceedings was declared, and Navalny told reporters: "I still hope everything will be fine."

The anti-corruption blogger, who helped organize the biggest anti-Putin protests since the former KGB spy first rose to power in 2000, is the most prominent opposition leader to be tried in post-Soviet Russia.

He has suggested Putin ordered the trial to stop his criticism of "swindlers and thieves" in power.