The White House attacked its own top Ukraine official as he testified to an impeachment hearing that a phone call made by the president was “improper” and had left him in “shock”.
Lt Col Alexander Vindman told Congress that President Donald Trump made “inappropriate” political demands of the Ukrainian president.
“I couldn’t believe what I was hearing,” Lt Col Vindman said.
The hearings are investigating whether Mr Trump abused his presidential power.
A decorated Iraq war veteran who serves in a senior role on the US National Security Council (NSC), Lt Col Vindman testified before the House on Tuesday in his Army dress uniform.