She was removed abruptly from her post in Ukraine in May, months ahead of her scheduled departure, after coming under attack from right-wing media, who alleged she was hostile to the president.
Yovanovitch says Sullivan told her Trump had been pressuring the State Department to remove her since the summer of 2018.
The investigation of Trump could lead to the approval of articles of impeachment - or formal charges - against the president in the House. But in her prepared remarks, obtained by Fox News, she denied asking any Ukrainian official to refrain from investigating corruption, and said it was "fictitious" that she was disloyal to the president. Trump has said he was investigating corruption, while Democrats have accused him of using USA military aid as a quid pro quo for an investigation into a political rival.
Yovanovitch was recalled from Kyiv in May as Rudy Giuliani - who is Trump's personal attorney and has no official role in the USA government - pushed Ukrainian officials to investigate baseless corruption allegations against the Bidens.
The email marks the second time the White House has unintentionally sent talking points to Democrats in recent weeks, after an administration official inadvertently emailed them suggested rhetoric defending the July 25 phone call. Neither Giuliani nor Trump has publicly specified their objections to Yovanovitch.
Parnas sought the help of a USA congressman to get Trump to remove Yovanovitch, according to the indictment.
The statement was released Friday, shortly before on the same morning that the former USA ambassador in Kiev, Marie Yovanovitch, testify about what she knows of the Trump administration's pressure effort on Ukraine. The former diplomat insisted on anonymity to disclose the private conversation.
ABC News has repeatedly asked the State Department for comment on Yovanovitch's planned appearance.
To compel her testimony, the House Intelligence Committee issued a subpoena Friday morning. The committees are scheduled to talk to several other USA diplomats next week, as well. Gordon Sondland, who had declined to testify earlier this week.
"He also said that I had done nothing wrong and that this was not like other situations where he had recalled ambassadors for cause", Yovanovitch said.
Sondland was originally scheduled for a deposition this past Tuesday but did not show up.
Yovanovitch is now being interviewed by House investigators behind closed doors as part of Democrats' impeachment inquiry.
His lawyers said that although Sondland will appear at the hearing, he will not be producing the "relevant documents" directed by the subpoena.
"Ambassador Sondland has at all times acted with integrity and in the interests of the United States", Mr. Luskin said.
The statement said, however, that Sondland would not be able to product documents "concerning his official responsibilities", as they were controlled by the State Department.
Sondland, a Trump political donor who contributed $1 million U.S. to the Republican president's inauguration committee, exchanged text messages about Washington's relationship with Ukraine with other top diplomats.
Yovanovitch is providing her deposition behind closed doors. She did not respond to questions posed by reporters.
President Donald Trump and Ukrainian President Volodymyr Zelenskiy looks on during a meeting in NY on September 25, 2019, on the sidelines of the United Nations General Assembly.
"As Mr. Lutsenko, the former Ukrainian Prosecutor General has recently acknowledged, the notion that I created or disseminated a "do not prosecute" list is completely false-a story that Mr. Lutsenko, himself, has since retracted", Yovanovitch said. "Today, we see the state department attacked and hollowed out from within".