US President Donald Trump said Vladimir Putin had “gone absolutely CRAZY” by unleashing the largest aerial attack of the war on Ukraine and said he was considering more sanctions on Moscow, but he also scolded Ukrainian President Volodymyr Zelenskiy.

“Something has happened to him. He has gone absolutely CRAZY!” Trump said of the Russian president on 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!”

Trump also criticised Zelensky, posting that the Ukrainian leader “is doing his Country no favours by talking the way he does. Everything out of his mouth causes problems, I don’t like it, and it better stop.”

Speaking to reporters at the airport in Morristown, New Jersey, Trump said of Putin: “I don’t know what’s wrong with him. What the hell happened to him? Right? He’s killing a lot of people. I’m not happy about that.” He raised the possibility of imposing more sanctions on Russia in response to the ongoing attacks.

The Kremlin on Monday said that US President Donald Trump’s claim that Vladimir Putin had “gone absolutely CRAZY” might be due to emotional overload, but thanked the US leader for his assistance in launching Ukraine peace negotiations.

“We are really grateful to the Americans and to President Trump personally for their assistance in organising and launching this negotiation process,” Kremlin spokesman Dmitry Peskov said when asked about the Trump remarks about Putin.

“Of course, at the same time, this is a very crucial moment, which is associated, of course, with the emotional overload of everyone absolutely and with emotional reactions.”

There was no immediate response Zelensky’s office on Trump’s remarks.

In the biggest aerial assault of the war, Russia pummeled Ukrainian cities and other targets with at least 367 drones and missiles overnight on Sunday, killing at least 12 people, including three children in the northern region of Zhytomyr, Ukrainian officials said.

The Russian attack was the largest of the war in terms of weapons fired, although other strikes have killed more people.

Trump has been pressuring Russia and Ukraine to end the more than three-year war, but the two sides remain far apart — and while major powers talk, the war is intensifying and Russian forces are advancing in eastern Ukraine.

Swarms of drones are being launched by both sides while fierce fighting is underway along key parts of the front.

The Kremlin says it is conducting what it calls a “special military operation” in Ukraine to protect Russia from Nato encroachment on its borders. Ukraine says Russia launched an unprovoked war of aggression.