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.

The U.S. Secret Service is preparing for the summit in the Central European nation led by Prime Minister Victor Orbán, who has been close with President Donald Trump since the American president’s first term in office. A spokesperson for the White House did not immediately respond to a request for comment.