After a hearing that was closed to the media, despite protests from Navalny and his lawyers, he stood in his black prison uniform and listened to judge Viktor Rogov rattle through the list of his convictions before telling him that his sentence was unchanged.

Navalny, 47, now faces a transfer to a "special regime" prison colony, the harshest grade in Russia's penal system, with the prospect of staying there until he is in his mid-70s.

He rejects all the charges against him, which have ranged over the years from fraud and contempt of court to an array of "extremist" activities, as attempts to silence his criticism of President Vladimir Putin.

Daniel Kholodny, a TV technician who worked for Navalny, was sentenced to eight years in jail in August as part of the same trial. His appeal too was rejected on Tuesday.

"Alexei, see you!" Kholodny shouted after the judge finished speaking. Navalny waved his hand in response.

"For all of us - their colleagues and friends - this is constant pain," Navalny aide Leonid Volkov posted on X, formerly Twitter. "And a constant challenge: every day to do everything we can to destroy the maniac in the Kremlin."

The Kremlin has tried to portray Navalny as politically irrelevant, and Putin makes a point of never speaking his name. Moscow has cast him as an extremist and, without providing evidence, as a puppet of the U.S. Central Intelligence Agency.

Navalny is by far the best known figure in Russia's splintered opposition, with supporters casting him as a Nelson Mandela-style figure who will one day be freed from jail to lead the country.

His political movement has been outlawed and its key figures have been jailed or fled abroad as part of a crackdown on dissent that has intensified since Putin launched his invasion of Ukraine last year.

Vladimir Kara-Murza, another outspoken Kremlin critic who was jailed for 25 years in April on charges of treason and lying about the war, was last week moved to a maximum-security penal colony in Siberia, according to his lawyer.

PUTIN NEVER SPEAKS HIS NAME

Navalny's latest 19-year sentence was imposed on Aug. 4 after he was convicted on six charges related to alleged extremist activity, all of which he denied.

That came on top of 11-1/2 years he was already serving at the IK-6 penal colony at Melekhovo, about 235 km (145 miles) east of Moscow, on fraud and other charges which he also rejected as politically motivated.

Navalny earned admiration around the world for voluntarily returning to Russia in 2021 from Germany, where he underwent treatment for what Western laboratory tests showed was an attempt to poison him with a nerve agent in Siberia.

He was immediately arrested on arrival. The Kremlin denied it had tried to have him killed, with Putin commenting: "If someone had wanted to poison him, they would have finished him off."

The latest charges and sentence relate to his role in his now-defunct movement inside Russia, which the authorities accused of trying to destabilise society.

The U.S. State Department called the August verdict "an unjust conclusion to an unjust trial", while the European Union condemned what it called another politically motivated ruling and called for Navalny's immediate release.

Navalny said after the verdict last month that the aim was to crush Russians' will to stand up to Putin, and urged people not to give up.

"You are being forced to surrender your Russia without a fight to the gang of traitors, thieves and scoundrels who have seized power," he said.

"Putin must not achieve his goal. Do not lose the will to resist."