Ex-top Trump Russia aide to testify about 'shadow policy' on Ukraine: report

President TrumpDonald John TrumpThis week: House kicks off public phase of impeachment inquiry Impeachment week: Trump probe hits crucial point Judd Gregg: The big, big and bigger problem MORE's former top assistant working on European and Russian issues will reportedly testify to Congress that Trump's top lawyer, Rudy GiulianiRudy GiulianiImpeachment week: Trump probe hits crucial point This week: House kicks off public phase of impeachment inquiry Giuliani associate says he sought to pressure Ukraine to investigate Bidens MORE, and his associates set up a shadow foreign policy for the Trump administration relating to Ukraine that circumvented the National Security Council (NSC).

NBC News reported Thursday that Fiona Hill, a former special assistant to the president, will tell House lawmakers that Giuliani and Trump's ambassador to the European Union, Gordon Sondland, went around the NSC and official White House procedures to speak to the president about Ukraine.

ADVERTISEMENT

Hill's attorney did not immediately return a request for comment from The Hill.

Her impending testimony is said to have caused worry in the White House, as Hill's tenure as one of Trump's top advisers stretches to the earliest months of his presidency.

Hill left the Trump administration in June after serving under two national security advisers, H.R. McMaster and John BoltonJohn BoltonImpeachment week: Trump probe hits crucial point Swalwell: Depositions provided evidence of an 'extortion scheme' Intelligence panel Democrat: 'I think we will end up calling' some witnesses on GOP list MORE, the latter of whom was ousted from the Trump administration last month.

Considered by many to be a top expert on Russian President Vladimir PutinVladimir Vladimirovich PutinBiden expresses shock that Trump considers attending Russia May Day event Harris swipes at Trump on Russia: 'Always nice to spend time with supporters on the campaign trail' Trump says he's considering attending Russia's May Day parade MORE, Hill is the first former White House official to agree to comply with House Democrats' impeachment inquiry.

The probe was launched in response to a controversial conversation between the president and Ukraine's President Volodymyr Zelensky during which Trump pressed Zelensky to investigate former Vice President Joe BidenJoe BidenImpeachment week: Trump probe hits crucial point Trump DACA fight hits Supreme Court Juan Williams: Honesty, homophobia and Mayor Pete MORE, a top 2020 Democratic contender for president.

The White House has opted to use executive privilege to stop officials from testifying before Congress, but it remains legally unclear if the president can force former officials who are now private citizens from testifying.