(ANSA-AFP) - WASHINGTON, AUG 18 - Ukrainian President Volodymyr Zelensky headed to a high stakes meeting with Donald Trump Monday, backed by a phalanx of European leaders, in hopes of bridging a growing gulf with his US counterpart on a peace deal with Russia. Trump is pushing Ukraine to make major concessions following his summit with Russian President Vladimir Putin in Alaska last week, saying Kyiv must give up Crimea and abandon its NATO ambitions. Those are two of Moscow's top demands. But Zelensky, who huddled with the Europeans before they all went to the White House to meet Trump, urged Trump to bring "peace through strength" against Russia and stressed the need for US security guarantees. Trump and Zelensky will first meet one-on-one in the Oval Office -- with all eyes on whether there will be a repeat of the astonishing scenes in February when the US president and his deputy JD Vance publicly berated the Ukrainian. Trump, 79, said it was a "big day at the White House" and appeared to be in a combative mood, churning out a string of social media posts. "I know exactly what I'm doing," the Republican said on his Truth Social network. "And I don't need the advice of people who have been working on all of these conflicts for years, and were never able to do a thing to stop them." Trump will later meet separately with the leaders of Britain, France, Germany, Italy and Finland, as well as NATO chief Mark Rutte and European Commission chief Ursula von der Leyen. (ANSA-AFP).