A Russian court Tuesday found jailed Kremlin critic Alexei Navalny guilty of additional charges of embezzlement and contempt of court and sentenced him to nine years in prison as Moscow seeks to wipe out remaining pockets of dissent.

The sentencing came on the 27th day of what Moscow has termed a "special military operation" in pro-Western Ukraine, with thousands killed and some 10 million displaced.

"Navalny committed fraud -- the theft of property by an organised group," judge Margarita Kotova said, according to an AFP reporter present at the hearing held inside Navalny's penal colony outside Moscow.

The judge also found Navalny guilty of the less severe charge of contempt of court.

His lawyers were detained by police outside the prison following the verdict, according to an AFP reporter on the scene.

Navalny, President Vladimir Putin's most vocal domestic critic, will serve his new sentence in a "strict-regime" penal colony which will place him in much harsher conditions.

The nine-year sentence will run concurrently with the term is he already serving.

Last year the Russian opposition leader was sentenced to two and a half years for violating parole over old fraud charges while recovering from a poison attack with Novichok nerve agent that he blames on the Kremlin.

Navalny will also have to pay a fine of 1.2 million rubles ($11,500), the judge said.

Navalny appeared in the makeshift court wearing his black prison uniform, with journalists watching via a video link.

He listened closely as judge Kotova read out the verdict, sometimes smiling, an AFP reporter said. 

Investigators accused Navalny of stealing for personal use several million dollars' worth of donations that were given to his political organisations.

The prosecutor had last week called for Navalny's sentence to be extended to 13 years as well as for his transfer to a strict- regime penal colony.

Navalny denied the charges, saying they were punishment for challenging 69-year-old Putin.

Historic crackdown 

Russia is seeing an unprecedented crackdown on the opposition and dissenting voices.

Before he was jailed, Navalny was Russia's main opposition leader and his team frequently published investigations into the wealth of Russia's elites that garnered millions of views on YouTube. 

Navalny's poisoning in 2020 with Novichok, a military-grade nerve agent, and arrest on his return from rehabilitation in Germany last year, sparked widespread condemnation abroad, as well as sanctions from Western capitals.

After his arrest, Navalny's political organisations across the country were declared "extremist" and shut down, while key aides have fled Russia fearing prosecution. 

Russia has also ramped up pressure on independent media and NGOs, declaring many to be "foreign agents", while others have stopped operating for fear of prosecution. 

More closures of media outlets followed after Russia passed a new law introducing up to 15 years in jail for "fake news" about Russia's military action in Ukraine.

In an effort to further control the information available to its domestic audience, Russia this month restricted access to Twitter, Facebook and Instagram, and has blocked the websites of several independent news outlets.

On Instagram, Navalny has denounced the conflict in Ukraine and called on his supporters to protest despite the high likelihood of fines and arrest.

More than 15,000 people have been detained at Ukraine demonstrations across Russia after Putin sent troops to Ukraine on February 24, says independent monitor OVD-Info.