"The harm will come when private interests circumvent professional diplomats for their own gain, not the public good", she said. He said Trump was not leveraging military aid to get Zelensky to launch an investigation into a political rival.
She will likely be asked about USA military aid to Ukraine and details about the administration's decision to withhold that aid.
In her written deposition to Congress, Yovanovitch gave a description of the events surrounding her surprise removal from her post in Kyiv, weeks after having been told in March that the state department wanted her to extend her posting till 2020. She also took direct aim at Giuliani's associates whom she said could've been financially threatened by her anti-corruption efforts in Ukraine.
She arrived on Capitol Hill on Friday despite the White House's stated objections and refusal to cooperate with the Democrat-led proceedings.
Trump had said in August he was considering Sullivan for the envoy job.
Her statement revealed no new details about the circumstances surrounding Trump's call with Zelensky about Biden. Guliani has made several trips to Ukraine on Trump's behalf.
She did not answer questions from reporters as she entered the building.
On Thursday, two foreign-born Florida businessmen who had helped Giuliani investigate Biden were arrested in what prosecutors said was a scheme to illegally funnel money to a pro-Trump election committee and other USA political candidates.
Appeals court rules House should get Trump financial records
On Thursday, Deutsche Bank told a United States appeals court that they did not have copies of Trump's tax returns. The House has made that point increasingly explicit even as it attempts to avoid making it formal .
The two had donated $325,000 to a pro-Trump political action committee called America First Action in May 2018, and the money was falsely reported as coming from a purported natural gas company set up to hide its true source, according to the indictment. House Democrats launched an impeachment inquiry to investigate Trump after a U.S. intelligence official filed a whistleblower's complaint about a July 25 call between the United States president and Ukrainian President Volodymyr Zelenskiy. A trial on whether to remove him from office would then be held in the U.S. Senate, where the Republicans who control the chamber have shown little appetite for ousting the president.
The chairmen said efforts by the Trump administration "will be deemed obstruction" in their impeachment inquiry. "This entire proceeding is unworthy of cooperation", he said.
Yovanovitch has led US embassies in Kyrgyzstan and Armenia and is now a State Department fellow at Georgetown University.
The resignation this week of Michael McKinley, a career diplomat and senior adviser to Pompeo, came amid rising dissatisfaction inside the State Department at what is seen as Pompeo's failure to defend his subordinates who became targets in the Ukraine controversy.
"He added that there had been a concerted campaign against me, and that the Department had been under pressure from the president to remove me since the summer of 2018".
Interested in Impeachment Inquiry?
Marie Yovanovitch, the former US ambassador to Ukraine, told House impeachment investigators during a closed-door session Friday that President Donald Trump pressured the State Department to oust her after a "concerted campaign" of attacks led by Trump's personal attorney Rudy Giuliani.