Special U.S. envoy Steve Witkoff says Russian leader Vladimir Putin agreed to allow the U.S. and Europe to offer Ukraine a security guarantee resembling NATO's collective defense mandate.

U.S. President Donald Trump could offer NATO-like protection of Ukraine, and Russia is open to the idea, one of his top foreign policy officials said on Sunday ahead of a meeting with Ukraine and European leaders to hammer out details of possible security guarantees for Kyiv.

Ukrainian President Volodymyr Zelenskyy is bringing with him to the the White House an extraordinary cadre of European leaders to show U.S. President Donald Trump a united front against Russia.