U.S. President Donald Trump says he has called Russian President Vladimir Putin and begun to arrange a meeting between Putin and Ukrainian President Volodymyr Zelenskyy, a critical step toward bringing a possible end to Russia's war on Ukraine.

President Trump has offered only vague assurances of security guarantees for Ukraine if President Volodymyr Zelensky agrees to cut a deal with Russia.

President Trump and European leaders met for a one-of-a-kind summit at the White House on Monday to push toward a peace deal between Russia and Ukraine. But by the end of a marathon day of meetings, details on what such an agreement might entail remained elusive.

U.S. President Donald Trump told President Volodymyr Zelenskiy on Monday that the United States would help guarantee Ukraine's security in any deal to end Russia's war there, though the extent of any assistance was not immediately clear.

Ukraine will promise to buy $100bn of American weapons financed by Europe as part of a deal to obtain US guarantees for its security after a peace settlement with Russia, according to a document seen by the Financial Times.

President Donald Trump says the U.S. could support a European force in Ukraine to maintain a lasting peace in Russia's war.

President Volodymyr Zelenskiy accused Russia of unleashing "cynical" attacks on Ukrainian civilians that he said were designed to undermine his talks with U.S. President Donald Trump in Washington later on Monday.

Before and after the summit between President Donald Trump and President Vladimir Putin in Alaska, Ukraine has been assaulted with a barrage of Russian drone attacks and bombs.