A Russian military court on Tuesday sentenced a man to 14 years in prison on treason charges for allegedly planning an attack after joining a banned pro-Ukrainian militia unit.Artem Sanzharaev was accused of being a member of the Freedom of Russia Legion, a pro-Ukrainian unit made up of Russian citizens that has claimed responsibility for armed incursions into Russian border regions.A court in the Siberian region of Krasnoyarsk handed down a 14-year sentence, saying Sanzharaev was a "convinced ideological opponent" of Russia who was "dissatisfied with the current political regime."Prosecutors accused him of purchasing materials needed to make a Molotov cocktail "to undermine Russia's economic security and defense capacity," the court said.Security services foiled Sanzharaev's attempted attack on an electrical relay cabinet, it added.Russia has arrested dozens of its citizens on charges of collaborating with Ukraine since it launched the full-scale invasion in February 2022.