The five men asked the House and the Senate to hold hearings “to assess the national security implications of Mr. Trump’s dismissals.”

U.S. President Donald Trump has frozen military aid to Ukraine, just days after publicly confronting Ukrainian President Volodymyr Zelenskiy at the White House and accusing him of being insufficiently grateful for Washington's backing.

It's a major blow that threatens to remove some of the most formidable weapons in Ukraine’s battlefield arsenal.