A Russian court on Wednesday sentenced a man to six years in jail for online messages denouncing Russia's invasion of Ukraine, as Moscow clamps down on public criticism of the conflict.Nikolai Farafonov, 35, was found guilty of "public incitement to commit terrorist acts" by a military court in Russia's northern republic of Komi, local media reported.The prosecution said he had published "videos and messages" calling for the burning of military recruitment offices.Several dozen arson attacks or attempted attacks on such premises have been reported in Russia since the war began two years ago.The NGO Memorial, which referred to Farafonov as a political prisoner, said he lived in a small town in the region and ran a channel on the Telegram messaging service openly hostile to the conflict.On the channel, Memorial said he referred in particular to Russian soldiers being killed in Ukraine, while criticizing political repression, "patriotic" pro-Kremlin education in schools and other local issues.Farafonov had previously been fined in October 2022 for "discrediting" the army following an online commentary that Memorial said referred to the deaths of Ukrainian children at the point of Russian bayonets.Despite the fine Farafonov continued to publish critical messages until he was arrested last September for "calls for terrorism."Thousands of Russians have been fined and hundreds jailed for denouncing President Vladimir Putin's attack on neighboring Ukraine, which was launched in February 2022.