The Democratic chairmen of the three House committees leading the probe discovered that the State Department on Thursday had directed Yovanovitch not to testify, they said in a statement. "State Department leadership, with Congress, needs to take action now to defend this great institution, and its thousands of loyal and effective employees", she said.
Yovanovitch told lawmakers investigating Trump's dealings with Ukraine that there was a "concerted campaign" against her based on "unfounded and false claims by people with clearly questionable motives". There has been no evidence of wrongdoing by the Bidens.
"It is clear to me that she was sacked because she was a thorn in the side of those who sought to use the Ukrainian government for their own political and financial gain - and that includes President Trump", Maloney said. "We also believe that, in return, our government will have our backs and protect us if we come under attack from foreign interests", she said.More news: Mastercard, Visa, EBay, Others Exit Facebook's Libra Coin Project
According to a federal indictment made public on Thursday, two associates of Giuliani's pressed a sitting US congressman to ask for Yovanovitch's removal previous year.
U.S. Ambassador to the European Union, Gordon Sondland, a key figure in the Ukraine controversy, bucked the State Department on Friday and announced he would appear before House investigators under subpoena next week.
Earlier on Friday, Trump cast doubt over whether former Giuliani will long be representing him, when he said he "has been" his attorney. Those men, Lev Parnas and Igor Fruman, have connections to Giuliani's attempts to dig up dirt on Joe and Hunter Biden, and they were arrested on charges of violating campaign finance law.
One of the foreign-born businessmen arrested on Thursday, Parnas, sought the help of a US congressman - identified by a person familiar with the matter as Republican Pete Sessions - to get Trump to remove Yovanovitch, according to the indictment.
Mr Giuliani had been working in Ukraine to press the authorities there to investigate widely debunked corruption allegations against Mr Biden, and his son, Hunter, who was associated with a Ukrainian company.More news: Goldman Reviewing Involvement in Chinese AI Firm's IPO
Yovanovitch defied a state department instruction not to speak to congressional committees leading impeachment proceedings against Donald Trump.
Yovanovitch, who is now a senior State Department fellow at Georgetown University, is likely at the end of her diplomatic career.
One of the Times' sources says the investigation is related to Giuliani's efforts to undermine former U.S. Ambassador to Ukraine Marie Yovanovitch. Zelensky said he agreed "100%".
The conversation occurred after Trump withheld $391 million in security assistance to Ukraine as it faces Russia-backed separatists in the eastern part of the country.
US President Trump's personal lawyer Rudy Giuliani pushed for removal of Yovanovitch. Former Rep. Pete Sessions (R-TX) wrote a letter to Secretary of State Mike Pompeo in May 2018 asking that he consider terminating Yovanovitch from her post.More news: Volvo XC40 Electric Shows New Android-Powered Infotainment
Eric Rubin, president of the American Foreign Service Association that represents USA diplomats, said Yovanovitch's testimony was in "the proud tradition of our nation's Foreign Service, emphasizing non-partisan commitment to our country's interests and loyalty to our country's elected leaders".