Vindman, who listened in on Trump’s call with Zelensky, told investigators that the president undermined U.S. national security when he pressured his foreign counterpart to investigate former Vice President Joe Biden and his son, according to a copy of Vindman’s opening statement obtained by POLITICO.

The New York Times and The Wall Street Journal reported that Vindman also testified that the White House’s readout of the call had missing words and phrases, and that he was unsuccessful in attempting to restore all the omissions to the rough transcript.

But Perry’s remarks Wednesday appear to provide the first on-the-record acknowledgment of those details of Vindman’s testimony.

“The words, generally speaking, that were replaced have already been kind of noted elsewhere, either in the call or in conjecture,” Perry said. “So it might be significant in some people's mind. It might be just inartful, and just a clerical discrepancy.”

Perry, however, declined to comment on what the two leaders allegedly discussed during the parts of the call left out of the official White House summary. He refused to confirm reports that Vindman said that Trump referred to recordings of Biden talking about corruption in Ukraine and that Zelensky mentioned Burisma Holdings, the Ukrainian energy firm on whose board Biden’s son, Hunter, sat.

“I'm not allowed to divulge what was said in the hearings for — because of a potential ethics violation,” Perry said, adding: “I don't think that that part was part of his opening statement, so I got to be careful what I talk about the particulars there. So I just can't get into that.”

Trump and Zelensky's conversation lies at the heart of House Democrats' escalating impeachment inquiry, as does a whistleblower complaint describing alleged efforts by White House officials to “lock down” records of the call.

Sen. Lindsey Graham (R-S.C.) said Wednesday that while he did not doubt that Vindman is “doing what he thinks is right,” his addendums to Trump’s call with Zelensky did not meaningfully alter the discussion.

“I have read the transcript, and if you add his corrections in, it doesn't change anything for me,” Graham said.

Also on Wednesday, Senate Minority Leader Chuck Schumer (D-N.Y.) wrote to Army Secretary Ryan McCarthy to request a briefing on how Vindman is being protected after conservative media, the president and Trump attorney Rudy Giuliani attacked him publicly over his damaging testimony.

Schumer warned that “this vitriol … may result in professional reprisals and threats to his personal safety and that of his family,” adding: “It is incumbent on the Army to ensure that he is afforded the same protections as whistleblowers and protected from reprisal for testifying before Congress.”

Burgess Everett and Marianne LeVine contributed to this story.