U.S. Ambassador to the E.U. Gordon Sondland said behind closed doors Thursday that he was “disappointed” that President Trump told him to work with attorney Rudy Giuliani in dealings with the Ukrainian government.

Sondland is speaking to investigators as part of House Democrats’ impeachment inquiry. That inquiry is focusing on circumstances surrounding President Trump’s July 25 phone call with Ukrainian President Volodymyr Zelensky, in which Trump urged Zelensky to “look into” concerns about former Vice President Joe Biden’s conduct in the country, as well as Ukraine’s activities in the 2016 election.

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The State Department had initially blocked Sondland from speaking at a scheduled deposition earlier this month, but Sondland subsequently agreed to appear Thursday after House Democrats issued a subpoena.

According to his prepared remarks, the wealthy hotelier and philanthropist said how in May, he and the rest of the U.S. delegation that had attended the Zelensky inauguration a few days earlier debriefed Trump and White House aides on the new Ukrainian government.

“We asked the White House to arrange a working phone call from President Trump and a working Oval Office visit,” Sondland said. “However, President Trump was skeptical that Ukraine was serious about reforms and anti-corruption, and he directed those of us present at the meeting to talk to Mr. Giuliani, his personal attorney, about his concerns.”

According to Sondland, “it was apparent to all of us that the key to changing the president’s mind on Ukraine was Mr. Giuliani.”

Sondland says that he, Energy Secretary Rick Perry and U.S. envoy to Ukraine Kurt Volker were “disappointed” by the debriefing and the directive that they involve Giuliani: “Our view was that the men and women of the State Department, not the President’s personal lawyer, should take responsibility for all aspects of U.S. foreign policy towards Ukraine."

He went on to say that, facing a choice of either abandoning the goal of a Zelensky White House meeting or involving Giuliani, they chose the latter.

In talks with Giuliani, Sondland claims that the former New York City mayor mentioned both concerns about the 2016 election, and also Burisma Holdings — a Ukrainian gas company where Biden’s son Hunter sat on the board.

“But I did not understand, until much later, that Mr. Giuliani’s agenda might have also included an effort to prompt the Ukrainians to investigate Vice President Biden or his son or to involve Ukrainians, directly or indirectly, in the President’s 2020 reelection campaign,” he says, adding that while Giuliani mentioned Burisma, he did not know the connection to the Bidens.

“Again, I recall no discussions with any State Department or White House official about Former Vice President Biden or his son, nor do I recall taking part in any effort to encourage an investigation into the Bidens,” he will say.

Democrats have claimed that Trump used the withholding of military aid as a quid pro quo to pressure Zelensky to investigate Biden. Trump has denied a quid pro quo, saying he has only ever been concerned about corruption. Sondland is connected to that denial as he had texted with Bill Taylor, a top U.S. diplomat in Ukraine, arguing over allegations of a quid pro quo.

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“The President has been crystal clear: no quid pro quo’s of any kind,” Sondland texted Taylor in September. “The President is trying to evaluate whether Ukraine is truly going to adopt the transparency and reforms that President Zelensky promised during his campaign.”

In his remarks Thursday, Sondland said that that came after a call with Trump, where the president had said there was no quid pro quo “multiple times” after Sondland pressed him on it.

The ambassador was expected to address media reports that Fiona Hill, a former senior director to Russian and Eurasian affairs, told lawmakers on Monday that then-National Security Adviser John Bolton told her to notify a lawyer at the National Security Council about concerns over an alleged effort involving Sondland to pressure Ukraine on the investigations.

“I am not part of whatever drug deal Sondland and [acting White House chief of staff Mick] Mulvaney are cooking up,” Bolton allegedly told Hill, according to The New York Times.

In his remarks, Sondland says that he kept the NSC up to date with efforts regarding Ukraine and “nothing was ever raised to me about any concerns regarding our Ukrainian policy.”

“To put it clearly: Neither [Hill] nor Ambassador Bolton shared any critical comments with me, even after our July 10, 2019 White House meeting,” he said. “And so, I have to view her testimony — if the media reports are accurate — as the product of hindsight and in the context of the widely known tensions between the NSC, on the one hand, and the State Department, on the other hand, which had ultimate responsibility for executing U.S. policy overseas.”

Sondland’s appearance comes amid back-to-back witnesses' testimonies as part of the impeachment probe. On Wednesday, Michael McKinley, a career foreign service officer and Secretary of State Mike Pompeo’s de facto chief of staff, reportedly told investigators behind closed doors that he could no longer look the other way amid the Trump administration’s dealings with Ukraine, which were among the reasons he ended his 37-year career last week.

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On Friday, former U.S. Ambassador to Ukraine Marie Yovanovitch told lawmakers that she had been recalled after “unfounded and false claims by people with clearly questionable motives” and said that she did not know why she had apparently been targeted by Giuliani.

“But individuals who may have been named in the press as contacts of Mr. Giuliani may well have believed that their personal financial ambitions were stymied by our anti-corruption policy in Ukraine,” she said.

Fox News' Rich Edson and Gregg Re contributed to this report.