By Doina Chiacu, Elizabeth Piper and John Irish WASHINGTON/LONDON/PARIS (Reuters) -U.S. President Donald Trump and Ukrainian President Volodymyr Zelenskiy clashed again on Wednesday on efforts to end the three-year-old war in Ukraine,

"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.