It was imposed in August after he was convicted on six charges related to alleged extremist activity - which he denied.

The appeal was rejected by a judge in Moscow, with Mr Navalny - wearing a black prison uniform - joining by video link from prison.

Media were not allowed to witness proceedings apart from the reading of the verdict.

The 19-year sentence was imposed on top of 11 and a half years that he was already serving after being convicted of fraud and other charges.

Mr Navalny has said all the charges are politically motivated and an attempt to silence his criticism of President Vladimir Putin's repressive regime and the war in Ukraine.

His political movement has been outlawed and declared "extremist", with its main players either being jailed or fleeing Russia.

President Putin makes a point of never referring to Mr Navalny by name as part of an attempt by authorities to portray him as irrelevant.

The 47-year-old politician returned to the country voluntarily in 2021 after nearly dying when he was poisoned with a nerve agent in a suspected Russian plot.

He was immediately arrested when he landed and is imprisoned in Melekhovo, about 145 miles (235 km) east of Moscow.

Read more:
Who is the man some hope will overthrow Putin?

Mr Navalny said in the summer that he had been forced to listen to the same speech by President Putin for more than 100 days in a row.

A TV technician who worked for Mr Navalny, sentenced at the same trial in August, also had his appeal against an eight-year sentence rejected on Tuesday.

Daniel Kholodny shouted "Alexei, see you!" just before the video feed of the hearing ended, with Mr Navalny waving his hand in response.