TALLINN, Estonia (AP) — The Moscow City Court on Thursday convicted a former Ukraine rebel leader who called President Vladimir Putin cowardly of extremism and sentenced him to four years in prison.

Igor Girkin, who used the surname alias of Strelkov (shooter), was the most prominent leader of Russian-backed separatist fighters in Ukraine’s Donetsk region in 2014, when rebellion arose after the ouster of Ukraine’s Russia-allied president.

He returned to Russia and became a nationalist commentator and activist. He supported launching Russia’s war in Ukraine, but sharply criticized authorities for being inept and indecisive in carrying out the fight.