President Donald Trump’s personal lawyer, Rudy Giuliani, has said removing the US ambassador to Ukraine became imperative for him and Mr Trump.
The ex-US envoy, Marie Yovanovitch, fired abruptly in May, has been a key witness in impeachment proceedings against Mr Trump.
“I needed Yovanovitch out of the way,” Mr Giuliani told the New Yorker.
The House of Representatives votes this week on impeachment, a probe centered on Mr Trump’s Ukraine dealings.
Mr Trump is accused of pressuring Ukraine’s leader to dig up supposedly damaging information on a former Vice-President Joe Biden, a domestic political rival. The Republican president has denied all wrongdoing, dismissing the inquiry as a “witch hunt”.
The House Rules Committee is meeting to determine how the House debate should be conducted. Mr Trump faces two charges – abuse of power and obstruction of Congress.
The House debate, with votes expected on Wednesday or Thursday, will mark the third time in history that the lower chamber has discussed impeaching a president.
Why is Ms Yovanovitch important?
Ms Yovanovitch’s sudden dismissal has emerged as a key element of the inquiry. Speaking before the House Intelligence Committee last month, the 33-year veteran of the foreign service said she believed her anti-corruption efforts in Ukraine had incurred the ire of influential Ukrainians who sought to remove her.
The ambassador said she was shocked that her enemies appeared to find allies in the Trump administration, including Mr Giuliani.
Mr Giuliani’s interview with the New Yorker appears to confirm that Ms Yovanovitch’s dismissal was linked to investigations into Ukraine sought by Mr Trump.
The former New York mayor has become a central character in the Ukrainian affair and the Democrat-led impeachment inquiry. Testifying last month, the US ambassador to the EU Gordon Sondland said that Mr Trump directed him and other top diplomats to work with Mr Giuliani on Ukraine “at the express direction of the president”.
Ms Yovanovitch “was going to make the investigations difficult for everybody,” Mr Giuliani told the New Yorker.
On Monday evening, he appeared to reinforce this stance, telling Fox News’s Laura Ingraham that “of course” he had Ms Yovanovitch removed, claiming it was due to the diplomat’s misbehaviour. There is no evidence of any wrongdoing by Ms Yovanovitch.
Mr Giuliani visited Ukraine again last month, before meeting Mr Trump at the White House on Friday.
Asked about Mr Giuliani’s work in Ukraine, the president told reporters his lawyer “does it out of love”.
“He’s a great person who loves our country,” Mr Trump said. “He sees what goes on. He sees what’s happening.”
In an unrelated case, another associate of Mr Trump, Rick Gates, was sentenced on Tuesday to 45 days in jail and a $20,000 (£15,200) fine on counts of conspiracy and lying to federal investigators.
Gates, a former Trump campaign official, was one of six associates of Mr Trump charged in connection with special counsel Robert Mueller’s investigation into Russian interference in the 2016 US election. He pleaded guilty to the charges in February 2018.