President Donald Trump has lashed out at Russian President Vladimir Putin for “needlessly killing” Ukrainian civilians.

The U.S. president described the Russian president as “absolutely crazy”.

Mr Trump, in a post on Truth Social on Monday, expressed displeasure with Mr Putin amid a recent barrage of missiles launched at Ukraine.

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

He added, “He is needlessly killing a lot of people, and I’m not just talking about soldiers. Missiles and drones are being shot into cities in Ukraine for no reason whatsoever.

“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!'”

About 12 persons were killed and scores injured as Russia fired 367 drones and missiles into Ukraine late on Sunday.

Mr Trump also berated Ukraine President Volodymyr Zelensky, claiming he “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,” said the U.S. president.

He added, “This is a war that would never have started if I were president. 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.”