The Russian Supreme Court has upheld the sentences of two opposition activists, Sergei Udaltsov and Leonid Razvozzhayev.
In a March 18 ruling, the court also annulled a fine imposed on Razvozzhayev.
In July 2014, the Moscow City Court sentenced Udaltsov, the coordinator of the Left Front movement, and Razvozzhayev to 4.5 years in prison each for organizing mass riots in Russian regions and organizing an anti-Putin rally on Moscow's Bolotnaya Square in May 2012 that turned violent and left scores of protesters and police injured.
Razvozzhayev was also ordered to pay a 150,000 rubles ($2,430) fine for illegally crossing the border.
Investigators said the 2012 protest had been orchestrated by a Georgian politician, Givi Targamadze, who is not in Russia.
Based on reporting by TASS and Interfax