Talks between the U.S., Ukraine and European officials to end Russia's war in Ukraine faltered on Wednesday as U.S. Secretary of State Marco Rubio abruptly cancelled his trip to London and negotiations were downgraded.

Donald Trump will let Vladimir Putin keep almost all the territory he has seized from Ukraine under the terms of a proposed peace deal.

The U.K.'s former top diplomat, Sir William Hague, said it will be up to Europe to help Ukraine if the U.S. walks away.

"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.