The prosecution on Monday requested an eight-year jail term against firebrand leftist leader Sergei Udaltsov for his alleged instigation of Moscow's violent Bolotnaya riots in 2012, Interfax reported.
The same sentence was requested for Udaltsov's alleged accomplice Leonid Razvozzhayev, who also faces a fine of 150,000 rubles ($4,300), RIA Novosti said.
Prosecutors claim Udaltsov and his leftist allies, funded by a politician from Georgia — then an enemy of the Russian regime — staged clashes with police at an opposition rally on Moscow's Bolotnaya Square on May 6, 2012.
Udaltsov — who has weathered more than 100 arrests for unsanctioned protests during the course of his political career — has repeatedly claimed the case was fabricated in retribution for his anti-Kremlin campaigning.
News reports did not give a date for the ruling, which will be handed down by the Moscow City Court.
Udaltsov has remained under house arrest since February 2013. Razvozzhayev has been in pretrial detention since his extradition from Ukraine amid torture allegations in October 2012.
More than 600 protesters were briefly detained at Bolotnaya Square; 27 have since faced criminal prosecution.
Opposition leaders blamed the clashes on police having mishandled the crowd during what was meant to be a peaceful march. No law enforcement officers have faced prosecution over the riots.