"The White House has directed that I not respond to this question because of the constitutionally-based Executive Branch confidentiality interests that are implicated," Annie Donaldson said - a total of 212 times.

In a letter to Jerrold Nadler, Hicks' lawyer, Robert Trout, said they would provide documents from her time on the Trump campaign, and said she had also previously provided some documents in March, after Nadler sent out his original requests for information.

The subpoenas, seek both testimony and documents in connection with the committee's probe into whether President Donald Trump obstructed Special Counsel Robert Mueller's Russia investigation.