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.

Trump did not rule out the possibility of American troops helping to guarantee peace between Ukraine and Russia should the leaders reach an agreement.

President Donald Trump welcomed Ukrainian President Volodymyr Zelenskyy to the White House for a high-stakes meeting as the U.S. president pushed for a deal to end Moscow's war on its neighbor. A host of European leaders joined the pair.