The leaders of Germany, France, Britain and Italy are among those who flew to Washington, D.C. on short notice to attend meetings with President Trump and President Volodymyr Zelensky of Ukraine.

The ball is in Ukraine's court. That's President Trump's message to Ukrainian President Volodymyr Zelenskyy ahead of a high-pressure meeting Monday at the White House. It's a follow-up to Trump's meeting last week with Russian President Vladimir Putin.