U.S. President Donald Trump sharply criticized Russian President Vladimir Putin on Sunday following the most extensive Russian airstrike of the war in Ukraine, calling the Kremlin leader “absolutely CRAZY” and warning that his actions could spell disaster for Russia.

“Something has happened to him. He has gone absolutely CRAZY!” Trump wrote on his social media platform, Truth Social. “I’ve always said that he wants ALL of Ukraine, not just a piece of it, and maybe that’s proving to be right—but if he does, it will lead to the downfall of Russia!”

The former president’s comments come in the wake of Russia’s overnight assault that saw 367 drones and missiles launched across Ukraine, killing at least 12 civilians, including three children, and damaging infrastructure in more than 20 locations. Ukrainian authorities called it the most intense single attack of the war.

Despite his strong words for Putin, Trump also took aim at Ukrainian President Volodymyr Zelensky, accusing him of aggravating the situation. “He is doing his Country no favours by talking the way he does,” Trump said. “Everything out of his mouth causes problems. I don’t like it, and it better stop.”

Speaking later to reporters in Morristown, New Jersey, Trump reiterated his concern over Russia’s actions. “I don’t know what’s wrong with him,” he said of Putin. “What the hell happened to him? He’s killing a lot of people. I’m not happy about that.”

Trump added that his administration is considering additional sanctions against Moscow, though he did not elaborate on specific measures.

Neither the Kremlin nor Zelensky’s office responded immediately to the remarks.

The war in Ukraine has intensified in recent weeks, with Russia ramping up aerial bombardments and Ukrainian forces defending key front lines in the east. As diplomatic efforts struggle to gain traction, Trump has continued to call for a negotiated peace, but his mixed messaging and criticism of both leaders have drawn scrutiny at home and abroad.