"The Office of the Vice President is evaluating her request," Short said.

Williams was one of the few White House officials who listened to the July 25 phone call between Trump and Ukrainian President Volodymyr Zelensky that led to Trump’s impeachment. She said that Trump’s efforts to pressure Ukraine to investigate his political opponents were “unusual and inappropriate,” and “shed some light on possible other motivations” for the president’s order to freeze military aid to the U.S. ally.

She also provided investigators with a firsthand account of Pence’s Sept. 1 meeting with Zelensky, and testified that the very first question Zelensky asked Pence was about the military aid.

Williams also submitted additional classified evidence to House impeachment investigators about a phone call between Pence and Zelensky, according to House impeachment manager Adam Schiff.

Schiff (D-Calif.) asked the vice president to declassify the supplemental testimony last month, asserting that “there is no legitimate basis for the Office of the Vice President to assert that the information … is classified.”

Schiff brought up Williams’ supplemental testimony again on Wednesday, confirming that it contains information about Russia’s role in promoting the unsubstantiated theory that Ukraine rather than the Kremlin interfered in the 2016 election.

Pence’s office has so far refused to turn over a slew of documents that investigators requested in October.