We are working on all possible scenarios to protect Ukraine,” said President Volodymyr Zelensky, whose country was looking to European allies for support.

The U.S. move won’t have an immediate impact on the battlefield, where Kyiv’s forces are struggling to stem a relentless Russian offensive in eastern Ukraine. Ukrainian forces have slowed Russian advances along the roughly 1,000-kilometer (600-mile) front line, where Russia is slowly gaining ground at a huge human and material cost.

Zelenskyy said in a social media post that it is "time to make things right" with the Trump and his administration.