Yovanovitch was interviewed by House investigators in October for more than nine hours and has emerged as a key figure in the investigation into Trump’s efforts to persuade Ukraine's new government to commit publicly to investigate corruption and the president's political opponents.

In Trump's July 25 phone call with Ukrainian President Volodymyr Zelenskiy, Trump referred to Yovanovitch as "bad news."

Yovanovitch departed Ukraine in May, months ahead of her scheduled departure, after coming under attack from right-wing media, which alleged she was hostile to the president. Her departure set off alarm bells among Democrats in Congress but the State Department said at the time her exit was planned.

Yovanovitch testified to House investigators Oct. 11 that Trump had personally pressured the State Department to remove her, even though a top department official assured her that she had "done nothing wrong."

Yovanovitch said during her testimony that after she was abruptly recalled from her post in the spring, Deputy Secretary of State John Sullivan told her that the president had lost confidence in her.

Yovanovitch, a career diplomat who said she was informed of her ouster in April, said in her opening statement that she was "incredulous that the U.S. government chose to remove an ambassador based, as best as I can tell, on unfounded and false claims by people with clearly questionable motives."

She told House investigators that she found out during a 1 a.m. phone call that she was being called back for unspecified "security" reasons.

Yovanovitch recalled that Carol Perez, the director general of the Foreign Service, "said that there was a lot of concern for me, that I needed to be on the next plane home to Washington. And I was like, what? What happened? And she said, I don't know, but this is about your security. You need to come home immediately. You need to come home on the next plane."

According to the intelligence community whistleblower complaint at the heart of Democrats' impeachment inquiry, Yovanovitch's tenure was cut short because she had run afoul of the then-prosecutor general in Ukraine, Yuri Lutsenko, and President Trump's personal lawyer Rudy Giuliani, who had been working to pressure the Ukrainian government to investigate the Biden family.Lutsenko at one point alleged she had given him a "do not prosecute" list. The State Department has said the assertion was an outright fabrication and Lutsenko himself later walked back his comments.

Trump, speaking to reporters Monday on the White House lawn, said the the transcript of the July 25 call with Zelenskiy showed that "the president of Ukraine wasn't a fan of hers either."

"I'm sure she's a very fine woman. I just don't know much about her," Trump added about Yovanovitch.

According to the transcript released Monday, Yovanovitch said she had wanted Pompeo to issue a statement that said she had his "full confidence," but the request was turned down. Yovanovitch, according to the transcript, said that acting Assistant Secretary of State Philip Reeker told her they were exercising "caution" because any statement "could be undermined" by the president.

She also explained that she was in the dark about many of Giuliani’s actions, but that she believed he was unhappy that she recommended against granting a U.S. visa to the former Ukrainian general prosecutor Viktor Shokin. Shokin — who was ousted over his failure to crack down on corruption — now claims he was really fired for investigating an energy company linked to former Vice President Joe Biden's son Hunter Biden.

"The embassy had received a visa application for a tourist visa from Mr. Shokin, the previous prosecutor general. And he said that he was coming to visit his children, who live in the United States,” Yovonavich said. Embassy officials believed he "was ineligible for a visa, based on his, you know, known corrupt activities," she said.

She recommended the embassy turn down the visa.

"And the next thing we knew, Mayor Giuliani was calling the White House as well as the Assistant Secretary for Consular Affairs, saying that I was blocking the visa for Mr. Shokin, and that Mr. Shokin was coming to meet him and provide information about corruption at the embassy, including my corruption," she testified.

She also gave her reaction to finding out that Trump told the Ukrainian president in their July call that she was "going to go through some things."

"I was shocked. I was shocked and I was — I was shocked and I was apprehensive about what that meant," she said.