Vice President Mike Pence is disputing EU Ambassador Gordon Sondland's assertion that Pence, along with other top administration officials, was keenly aware of a campaign to pressure Ukraine to probe the Ukrainian-based energy company Burisma, the Bidens and Ukraine's role in the 2016 election as part of a quid pro quo arrangement, effectively tying up military aid to Ukraine.

In a statement released by the vice president's office, Pence's Chief of Staff Marc Short said the vice president "never had a conversation with Gordon Sondland about investigating the Bidens, Burisma, or the conditional release of financial aid to Ukraine based upon potential investigations."

"Ambassador Gordon Sondland was never alone with Vice President Pence on the September 1 trip to Poland. This alleged discussion recalled by Ambassador Sondland never happened," the statement added in reference to Sondland's public testimony before the House Intelligence Committee as part of their ongoing impeachment probe of President Trump.

In Wednesday's testimony, Sondland implicated both Pence and Secretary of State Mike Pompeo of having full knowledge of plans pushed by Mr. Trump attorney Rudy Giuliani to carry out an investigation of the former vice president and his son, as well as a debunked conspiracy theory that Ukraine was somehow involved in the election interference campaign in 2016.

Sondland also testified that he had mentioned to Pence directly his concerns in delaying key military aid to Ukraine as part of a quid pro quo arrangement to carry out Giuliani's investigations. He said the conversation happened on the sidelines of a meeting with Ukrainian President Volodymyr Zelensky in Warsaw.

"I mentioned to Vice President Pence before the meetings with the Ukrainians that I had concerns that the delay in aid had become tied to the issue of investigations," Sondland testified. "I recall mentioning that before the Zelensky meeting."

"This security aid was critical to Ukraine's defense and should not have been delayed. I expressed this view to many during this period. But my goal, at the time, was to do what was necessary to get the aid released, to break the logjam. I believed that the public statement we had been discussing for weeks was essential to advancing that goal," Sondland testified.

The written statement was the first time Pence's office directly answered a question about whether the vice president was aware of the request for investigations.

It's a point Pence neither confirmed nor denied during his appearance on "Face the Nation" last month. Asked four separate times if he was aware of the deal, Pence repeatedly changed course and reiterated there was "no quid pro quo" on the president's part.

"He did nothing wrong," Pence claimed.

"But are you saying that you did not ever hear of such a deal? Is that what I understand you're describing?" "Face the Nation" moderator Margaret Brennan pressed.

"I'm telling you that all of my interactions with the president, all of my conversations with President Zelensky, were entirely focused on issues of importance to the American people, ending corruption, enlisting more European support and supporting Ukraine in a way that would restore its territorial integrity and stand by Ukraine for its sovereignty," Pence replied.