The Kremlin said it reserves the right to use nuclear weapons if it faces aggression by Western countries. Overnight, Moscow attacked Kyiv, killing at least nine people.

The Ukrainian president has consistently rejected the suggestion that his country give up its claim to the Crimean Peninsula.

"This statement is very harmful to the Peace Negotiations with Russia," Trump said in a social media post. He said Crimea was lost years ago "and is not even a point of discussion." Zelenskiy on Tuesday reiterated that Ukraine will not recognize Russia's occupation of the Crimea.