Updated at 6:04 p.m.

On the morning of July 25, Lt. Col. Alexander Vindman was in the White House situation room, listening to a call between President Donald Trump and Ukraine's newly elected leader, Volodymyr Zelensky.

It was on that call that Trump uttered the words that would trigger the House's impeachment inquiry. Trump asked Ukraine's president to investigate—as "a favor"—former Vice President Joseph Biden and his son Hunter.

Vindman, the director for European affairs on the National Security Council, recounted Tuesday that he "couldn't believe" what he was hearing.

"What I heard was inappropriate," Vindman testified, during the third day of public testimony in the House impeachment inquiry. "And I reported my concerns to Mr. Eisenberg."

John Eisenberg, the top lawyer for the National Security Council and a former Kirkland & Ellis partner, has refused to sit for questioning in the House impeachment inquiry. But he figured prominently at Tuesday's hearing as House lawmakers delved into the internal White House alarm over Trump's apparent effort to leverage congressionally approved military aid to Ukraine for assistance against a domestic political opponent.

A White House representative on Tuesday said in a statement: "We have learned nothing new in today's illegitimate 'impeachment' proceedings. However, buried among the witnesses' personal opinions and conjecture about a call the White House long ago released to the public, both witnesses testified the July 25 transcript was 'accurate' and nothing President Trump has done or said amounts to 'bribery' or any other crime."

Eisenberg was named repeatedly as Vindman recounted twice raising concerns about the pressure campaign. The first time following a July 10 meeting in which Gordon Sondland, the U.S. ambassador to the European Union, pushed a pair of Ukrainian officials to investigate the Bidens. Vindman returned to Eisenberg after the July 25 phone call now at the center of the House's impeachment probe.

In some of the crucial exchanges of Vindman's testimony, Eisenberg was referred to simply as "the lawyer."

House impeachment lawyers Left to right, House counsel Daniel Goldman; Intelligence Committee Chairman Adam Schiff; Ranking Member Devin Nunes; and Republican counsel Stephen Castor. Credit: Diego M. Radzinschi / ALM

"The very same issue that prompted you to go talk to the lawyer ends up coming in that call with the president, is that correct?" asked U.S. Rep. Adam Schiff, D-California, the chairman of the House Intelligence Committee.

"That is correct," Vindman answered.

"And it is that conversion that once again led you back to the lawyer's office," Schiff asked.

"That is correct," Vindman replied.

Eisenberg has come under scrutiny for his role in moving a transcript of the July 25 call to a highly classified server, a step other officials have described as at odds with standard White House protocol. His defenders have asserted Eisenberg did nothing improper in securing the rough transcript, a move that would help eliminate any leaks of its contents.

In his testimony Tuesday, Vindman said he believed the transcript was transferred to that server intentionally, contradicting the testimony of former National Security Council official Tim Morrison, who said in a closed-door deposition that the transcript had been mistakenly moved to that system.

"When it was mentioned that [the transcript] was sensitive, it was an on-the-fly decision to segregate it in the other system," Vindman said.

Vindman said he did not view the move "as anything nefarious." He added that two "substantive items" were missing from the transcript: a reference to "recordings" and to Burisma, the Ukrainian energy company where Hunter Biden was a board member. He did not see the omissions as a "big deal."

"I'd say it's informed speculation that the folks that produce these transcripts do the best they can, and they just didn't catch the word," he said.

Morrison, joined by Cozen O'Connor senior counsel Barbara Van Gelder, testified that he wanted access to the transcript to be restricted. But, he said, "it was represented to me that it was a mistake" for the transcript to be placed on the highly classified server. Morrison said Eisenberg inquired about how the transcript was placed on the classified system and learned it was an "administrative error."

When the House Republicans' counsel, Steve Castor, asked to clarify that there was  no "malicious intent" in moving the transcript to the highly-secure server, Morrison replied, "Correct."

After reporting his concerns to Eisenberg about the July 25 call, Vindman said he spoke with State Department official George Kent and an intelligence community official, whom he declined to name. Vindman testified that Eisenberg circled back with him after hearing from the general counsel of "one of the intelligence bodies" about information on the call.

"At that point, Mr. Eisenberg said I shouldn't talk to anyone else about it," Vindman said.

Vindman was joined at Tuesday's hearing by his lawyer, Mike Volkov, and testified alongside Jennifer Williams, an adviser to Vice President Mike Pence. Williams also listened to the July 25 call and described it Tuesday as "unusual" for including a reference to a "domestic political matter."

She was accompanied by her lawyer, Justin Shur, a partner at MoloLamken, who at one point stepped in to prevent her from testifying about a call between Pence and Zelensky.

Shur said the vice president's office had deemed the call classified and told House lawmakers, "I've advised Ms. Williams to not answer further questions about that call in an unclassified setting."

Before they testified, Vindman delivered an opening statement in which he described Trump's personal lawyer, Rudy Giuliani, as a "disruptive" actor who undermined U.S. foreign policy toward Ukraine. Giuliani has been accused of running a shadow foreign policy to pressure Ukraine to investigate Biden and also a debunked theory that the country interfered in the 2016 U.S. presidential election.

"It is improper for the president of the United States to demand a foreign government investigate a U.S. citizen and political opponent," Vindman said.

Later, he said he relayed his concerns about the Trump administration's dealings with Ukraine "out of a sense of duty."

At the end of Tuesday's hearing, a Republican lawmaker questioned whether Vindman had gone outside the chain of command in raising his concerns to Eisenberg rather than his direct supervisor, Morrison.

Schiff, in his closing remarks, came to Vindman's defense, saying that Morrison "didn't go to his supervisor either" following the July 25 call.

"He went directly to the National Security Council lawyer," Schiff said.