U.S. President Donald Trump said he believes his Russian counterpart Vladimir Putin is ready to end his war in Ukraine, speaking on the eve of Friday's summit between the men, but that peace would likely require at least a second meeting involving Ukraine's leader.

Ukrainian President Volodymyr Zelenskyy and his European allies have intensified their efforts this week to prevent any deal between the U.S. and Russia emerging from Friday's summit in Alaska that leaves Ukraine vulnerable to future attack.

"I think President Putin will make peace, I think President Zelenskyy will make peace," Trump told reporters at the White House. "We'll see if they get along."