Michael McKinley, a former top adviser to Secretary of State Mike Pompeo, told the House committees leading the impeachment probe that he resigned his post after a "puzzling and baffling" lack of support for the former US ambassador to Ukraine, according to a transcript of his testimony released Monday.
The transcripts were the first of what is expected to be more than a dozen separate interviews that will likely become public as Congress moves into its next phase of the ongoing impeachment inquiry.
Trump and his Republican allies are denying that the president committed an impeachable offense in July when he suggested in a phone call to Ukrainian President Volodymyr Zelensky that military aid would be withheld unless Ukraine opened an investigation into former Vice President Joe Biden.
Giuliani and his associates were specifically investigating the existence of a so-called "black ledger", which allegedly detailed millions of dollars in secretive payments from ousted pro-Russian Ukrainian President Viktor Yanukovych to former Trump campaign chair Paul Manafort, and whether it was used to convince USA authorities to reopen a case against Manafort.
According to her deposition, she was alarmed by the deepening involvement of Trump's personal lawyer Rudy Giuliani in Ukrainian affairs, and in particular his efforts to get Kiev to investigate Biden.
He also released testimony from Michael McKinley, a former senior advisor to Secretary of State Mike Pompeo who resigned in September after concluding that the department was not defending top diplomats.
This is a developing story.
Yovnoavitch said she was told that there was "caution" about putting any kind a statement, because it could be "undermined" by the President.
The ambassador said when she asked why, Ms Perez told her: "I don't know, but this is about your security". That apparently, as I stated in my statement, the President had been - had wanted me to leave since July of 2018 ... and that the Secretary had tried to protect me but was no longer able to do that, ' she said in her testimony.
Mr Trump dismissed her testimony Monday as he left the White House for a rally in Kentucky.
Yovanovich was pushed out of her job in May on Trump's orders.
She was asked: "Did he actually say, 'support President Trump"?
Lawmakers were especially interested in questioning the lawyer, John Eisenberg, who took the unusual step of moving a transcript of the call into the White House's most classified computer system, according to a person familiar with last week's testimony by Army Lieutenant Colonel Alexander Vindman, who listened in on the call. He told the secretary of state he was resigning in part because of the "lack of public support for Department employees".
The former envoy stressed to investigators that she was not disloyal to the president.
Yovanovitch said she felt she could not follow that advice.
Yovanovitch replied: "Well, clearly, they didn't want me in Ukraine anymore".
"Until today, nobody has ever actually asked me the question from the United States government of whether I am actually guilty of all of these things I'm supposed to have done", she said.
"Honestly", she said, "it's a mystery to me".