Chechen strongman Ramzan Kadyrov threatened Volodymyr Zelensky on Sunday and said he thinks the Ukrainian president has a serious mental disorder.

Kadyrov, one of Russian President Vladimir Putin’s top allies, accused Zelensky of having schizophrenia and said in an audio message posted on his Telegram account, “We will finish with you one of these days.” The leader of the Chechen Republic of Russia was responding to comments made by Zelensky on Sunday in which the Ukrainian leader said his country is prepared to fight Russian forces for “10 years to take what’s ours.”