Newly released government emails shows the White House sought to freeze aid to Ukraine just 90 minutes after President Trump spoke to President Volodymyr Zelensky by phone in July.
In the call, Mr Trump asked the Ukrainian leader to investigate his political rival, Democrat Joe Biden.
The email obtained by the Center for Public Integrity following a court order in a freedom of information case, shows that Mike Duffey, a senior White House official, contacted senior defence officials about withholding Ukraine’s aid.
Democrats say it shows Mr Trump used his office for personal political gain.
The phone call is key to the abuse of power charge on which Mr Trump has been impeached.
