Aides to Vice President Mike Pence, who has been trying to keep his distance from the House impeachment investigation, said Wednesday he never talked with the U.S. ambassador to the European Union about the issues under investigation.

Gordon Sondland, who played an unusual role in shaping U.S.-Ukraine policy, testified Wednesday that on the day before Pence was to meet with Ukraine President Volodymyr Zelensky, Sondland mentioned the need for Ukraine to announce investigations into former Vice President Joe Biden, Biden’s son and a debunked conspiracy theory in exchange for an Oval Office meeting between President Trump and his Ukrainian counterpart. At the time, the U.S. also was withholding $391 million in military aid.

“I mentioned to Vice President Pence before the meetings with the Ukrainians that I had concerns that the delay in [U.S. military aid to Ukraine] had become tied to the issue of investigations,” Sondland said. “I recall mentioning that before the Zelensky meeting.”

He added: "I don’t know exactly what I said to him. This was a briefing attended by many people and I was invited at the very last minute — I wasn’t scheduled to be there. But I think I spoke up at some point late in the meeting and said it looks like everything is being held up until these statements get made and that’s my, you know, personal belief."

He said Pence acknowledged his words but didn’t say anything.

"We believe very strongly that this never happened," a Pence aide said.

Pence spokesman Marc Short said the vice president never talked with Sondland “about investigating the Bidens, [Ukraine energy company] Burisma, or the conditional release of financial aid to Ukraine based upon potential investigations.”

His statement added: “Ambassador Gordon Sondland was never alone with Vice President Pence on the Sept. 1 trip to Poland. This alleged discussion recalled by Ambassador Sondland never happened.”

Investigators already were interested in any role Pence may have played and questioned earlier witnesses on why he didn't attend Zelensky's inauguration after the administration initially said he would.