President Trump on Sunday urged Republicans privy to last week's House Intelligence Committee hearings to come forward with their own transcripts from the closed-door meetings that Democrats claim bolstered their claim for impeachment.

Trump also appeared to suggest that he has information that a recent witness, Lt. Col. Alexander Vindman, is a “Never-Trumper.” He was asked about any evidence he may have about Vindman and he responded, “We’ll be showing that to you real soon.”

WHISTLEBLOWER NOT WILLING TO TALK TO REPUBLICANS

The president is under an impeachment investigation over allegedly withholding millions in defense funding from Ukraine in order for Kiev to investigate the Bidens’ business relationships in the country.

"If Shifty Adam Schiff, who is a corrupt politician who fraudulently made up what I said on the “call,” is allowed to release transcripts of the Never Trumpers & others that are & were interviewed, he will change the words that were said to suit the Dems purposes: Republicans should give their own transcripts of the interviews to contrast with Schiff’s manipulated propaganda," he tweeted.

Trump's tweet alluded to the July 25 phone call with Ukraine’s President Volodymyr Zelensky that the whistleblower referred to as “frightening.” Trump also attacked Schiff over his inaccurate, exaggerated version of a transcript of the call. Trump has said in the past that Schiff may have had a "mental breakdown" and may have committed a crime. Schiff himself later apologetically acknowledged it was a "parody."

Trump has suggested that the impeachment investigation is simply another attempt by Democrats to damage his presidency after the Mueller report fell short.

Democrats point to recent closed-door testimony as evidence of unscrupulous dealings between the Trump administration and Ukraine.

Vindman, in prepared remarks, wrote: “I did not think it was proper to demand that a foreign government investigate a U.S. citizen, and I was worried about the implications for the U.S. government’s support of Ukraine.”

He added, “Following the call, I... reported my concerns to NSC’s lead counsel,” a reference to top NSC lawyer John A. Eisenberg.

Both Trump and Zelensky deny any wrongdoing.

Vindman testified in a closed-door hearing about his concerns about the president’s phone call and a prior meeting with Ambassador Gordon Sondland about investigating Joe Biden and his son.

Gen. Joe Dunford, the recently retired chairman of the Joint Chiefs of Staff, gave a full-throated endorsement of Vindman citing his honesty, patriotism and integrity. “He’s just a guy doing his job,” Dunford told Fox News.

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He went on to say that Vindman was “professional, competent, patriotic and a loyal officer. He’s made an extraordinary contribution in peacetime and in combat.”

Fox News' Gregg Re and Adam Shaw contributed to this report