A columnist and vocal critic of the Kremlin was arrested in Moscow after he claimed the war in Ukraine would be the end of Russian President Vladimir Putin’s reign, his wife said in a social media post Monday.

The arrest of Vladimir Kara-Murza, a Washington Post contributor known for his criticism of Putin, on unspecified charges is the latest attempt to punish anti-Kremlin rhetoric, Evgenia Kara-Murza, the columnist’s wife, said.