Former US President Donald Trump will be “against Americans” if he chooses to support Russia over Ukraine, the war-torn country’s President Volodymyr Zelensky said Sunday.

Speaking to CNN’s Kaitlan Collins in Kyiv, Zelensky said he “can’t understand how Donald Trump can be on the side of (Russian President Vladimir) Putin.”

“It’s unbelievable,” he added.

Trump, who is now almost certain to become the Republican presidential nominee after winning the South Carolina Republican primary, has in the past refused to say whether he supports Russia or Ukraine.

Zelensky said that he believed Trump — who also said he would end the conflict in one day if elected — did not understand Putin’s goals.

“I think Donald Trump doesn’t know Putin,” Zelensky said. “I know he met him… but he never fought with Putin. (The) American army never fought with the army of Russia. Never… I have a better understanding,” he said.

“I don’t think he understands that Putin will never stop,” he said.

/CNN