LONDON (REUTERS) - Jailed Russian opposition leader Alexei Navalny on Tuesday (May 24) lambasted President Vladimir Putin in a live court hearing, casting him as a someone who had started a "stupid war" in Ukraine based on lies.

"This is a stupid war which your Putin started," Navalny, 45, told an appeal court in Moscow via video link from a corrective penal colony. "This war was built on lies."

Navalny, by far Russia's most prominent opposition leader, was appealing against a nine-year jail sentence he was handed in March for fraud and contempt of court, on top of two-and-a-half years he is already serving. He denies all the charges against him and says they were fabricated to thwart his political ambitions.

The appeal was later rejected.

Repeatedly interrupted by the judge during the hearing, Navalny cast the prosecution's "facts" as "lies" - and compared them to the lies he said Putin had used to begin the Feb 24 invasion of Ukraine.

"What do you want to achieve - do you want short-term control, to fight with future generations, fight for the future of Russia?" Navalny asked the court. "You will all suffer historic defeat."

Navalny said Putin's Russia was run by thieves and criminals who had become enemies of the Russian people.

The Kremlin has repeatedly dismissed Navalny's claims about Putin, who it says has won numerous fair elections in Russia since 2000 and remains by far the country's most popular politician. It has dismissed Navalny's claim that Putin is corrupt as nonsense.

Putin says the "special military operation" in Ukraine is necessary to demilitarise and "denazify" the country, and because the United States was using Ukraine to threaten Russia through Nato enlargement and Moscow had to defend against the persecution of Russian-speaking people. Ukraine and its Western allies reject these as baseless pretexts to invade a sovereign country.