WASHINGTON — Lt. Col. Alexander Vindman, a Ukraine expert who listened to President Donald Trump’s July call with Ukraine’s president, said “there was no doubt” that Trump was seeking political investigations of former vice president Joe Biden and his son Hunter Biden at a time when nearly $400 million in U.S. military aid was being withheld, according to a transcript of his deposition.

The transcript was one of two made public Friday by House impeachment investigators, who also released one documenting the deposition of another National Security Council official, Fiona Hill, who also expressed concerns about efforts to pressure Ukraine.

A statement released by Democrats leading three committees involved in the impeachment inquiry emphasized that Vindman is an "active duty military officer who was awarded the Purple Heart after being injured by a roadside bomb in Iraq."

"Lt. Col. Vindman testified that the July 25, 2019, call between President Trump and the Ukrainian president [Volodymyr Zelensky] led him to report immediately to lawyers at the White House his serious concerns about political investigations the President pressed for on the call," the statement said.

"Lt. Col. Vindman also told the Committees that the 'demand' by President Trump for the announcement of a politically-motivated investigation into a U.S. citizen by a foreign country forced him to make a'moral and ethical' judgment, and led to his concern that the act could 'undermine U.S. national security.' "

The three Democrats called Hill "a respected Russia and Ukraine expert who served as Lt. Col. Vindman's supervisor." They said she "detailed how senior officials at the White House, including national security adviser John Bolton, shared her serious concern about efforts before the July call to push Ukraine to undertake these politically-motivated investigations, and about her efforts, at Mr. Bolton's direction, to report this activity to senior White House officials."

The statement was issued by Intelligence Committee Chairman Adam Schiff, D-Calif., Foreign Affairs Committee Chairman Eliot Engel, D-N.Y., and acting Oversight and Reform Committee Chairwoman Carolyn Maloney, D-N.Y.

The release of the transcripts came Friday after acting White House chief of staff Mick Mulvaney defied a subpoena and skipped a scheduled closed-door deposition at the Capitol.

Mulvaney's outside counsel informed House investigators one minute before his scheduled deposition that he wasn't coming because he had "absolute immunity," an official working on the impeachment inquiry said.

House Democrats want to hear from Mulvaney who has direct knowledge of Trump's thinking behind withholding military aid from Ukraine and who said, before walking it back, that it was a quid pro quo.

"If the White House had evidence to contest those facts, they would allow Mr. Mulvaney to be deposed, as three chiefs of staffs of President Clinton were during his impeachment proceedings," said the official, who requested anonymity to discuss closed-door proceedings. "Instead, they're hiding and trying to conceal the truth from the American people."

Trump was asked by reporters Friday about his blocking aides from testifying being a possible obstruction of Congress charge.

"They're making it up," Trump said. "I don't want to give credibility to a corrupt witch hunt. I'd love for Mick to go up . . . except it validates a corrupt investigation."

Trump also said that the House should not be holding public hearings next week. Speaking to reporters at he departed the White House, Trump called the impeachment inquiry "a hoax."

Mulvaney's defiance comes as Democrats leading the inquiry continue to release more transcripts from previous depositions. In a transcript released Thursday, Deputy Assistant Secretary George Kent described Trump's shadow efforts to force Ukraine's leadership to open investigations that were political beneficial to Trump.

Meanwhile, in a break with her father and leading congressional Republicans, the president's daughter, Ivanka Trump, said it was "not particularly relevant" to know the identify of the whistleblower whose complaint sparked the impeachment inquiry.

Ivanka Trump, a senior White House adviser, spoke to the Associated Press during a trip to Morocco where she has been promoting a U.S. program aimed at helping empower women in developing countries.

She noted that the anonymous U.S. intelligence official whose complaint sparked the inquiry was not party to the controversial July call between President Trump and Ukraine's president.

"This is a third party who was not privy to the call and did not have firsthand information," Ivanka Trump said. "That is what was the catalyst for all of this discussion. But to me, it's not particularly relevant aside from what the motivation behind all of this was."

President Trump has repeatedly calling for unmasking the whistleblower, and congressional Republicans have said they will seek public testimony from him. Democrats say his testimony doesn't matter because his complaint has been corroborated by several witnesses.

Earlier this week, Donald Trump Jr., the president's eldest son, shared a post on Twitter that mentioned the alleged whistleblower by name.

Andrew Bakaj, a lawyer for the whistleblower, demanded in a letter to the White House dated Thursday that President Trump stop calling for the publication of the whistleblower's identity. The letter alleged that Trump's "reckless and dangerous" comments already had intimidated the whistleblower.

As they sought to discredit the impeachment inquiry, Republicans continued to focus Friday on tweets from 2017 in which Mark Zaid, also an attorney for the whistleblower, predicted Trump's impeachment.

"The fact that the whistleblower has now his attorneys who since the day the president took office were tweeting about a coup and how they had to get the president out of the office should be of concern to a lot of people," White House press secretary Stephanie Grisham said during an appears on the Fox Business Network.

Zaid referred to impeachment on Twitter in January 2017 after Trump fired Deputy Attorney General Sally Yates for refusing to enforce executive policies.

Zaid responded to his Republican critics Thursday.

"I live in the United States. Not Nazi Germany. Not Stalinist Russia. Not North Korea," he tweeted in response to Trump's son Eric's suggestion that he go to prison. "Here, we have the right to object to the policies - and indeed the person - who holds the office of president. I rep a lawful #whistleblower," he added. "Which country do all of you want to live in?"