U.S. President Donald Trump called Vladimir Putin “absolutely CRAZY” and said the Russian leader “is needlessly killing a lot of people, and I’m not just talking about soldiers” in a Truth Social post on Sunday.

The comments indicate that Trump’s position on the Kremlin is hardening as his attempt to broker an end to the Russian war falters with no breakthrough in sight. The post came after Russia launched a massive attack on Ukraine over the weekend, lobbing drones and missiles at 30 cities and villages and killing at least 12 people, including three children.

“Missiles and drones are being shot into Cities in Ukraine, for no reason whatsoever,” Trump said Sunday evening. “I’ve always said that he [Putin] 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!”

Trump’s criticism of the Russian president raises the prospect that the mood has shifted against Putin in the U.S. administration, which initially took a more sympathetic approach to Moscow’s position in the war. Trump has repeatedly blamed Ukraine’s President Volodymyr Zelenskyy for starting the conflict and for prolonging it, even though Russian forces launched a full-scale invasion in February 2022.

The weekend’s immense attack on Ukraine, just a week after Trump and Putin held a two-hour call to discuss a U.S.-proposed 30-day ceasefire, appears to have escalated the American president’s ire.

“I’ve always had a very good relationship with Vladimir Putin of Russia, but something has happened to him,” Trump said.

But while Trump’s post harshly criticized Putin, he also again took aim at Zelenskyy, who has long been the main outlet for his frustration over the war. Trump said Zelenskyy “is doing his Country no favors by talking the way he does. Everything out of his mouth causes problems, I don’t like it, and it better stop.”

Earlier, the Ukrainian president had said in a post on X that “the world may go on a weekend break, but the war continues, regardless of weekends and weekdays. This cannot be ignored. Silence of America, silence of others around the world only encourage Putin.”

Trump, who pledged to end the war in Ukraine in “24 hours” prior to being elected president, has struggled with that mammoth task. Sunday’s post follows repeated threats from the president and other administration officials to abandon ceasefire negotiations.

Trump appeared to dangle that prospect again on Sunday, saying: “This is Zelenskyy’s, Putin’s, and Biden’s War, not ‘Trump’s,’ I am only helping to put out the big and ugly fires, that have been started through Gross Incompetence and Hatred.”