(CNN) — U.S. Ambassador to the European Union Gordon Sondland was sent by President Donald trump to work with Rudy Giuliani on Ukraine, he told Congress Thursday, and was left with a choice: Abandon efforts to strengthen a key strategic Alliance or work to meet the demands of the President’s personal lawyer.

Sondland said he did not know until “much later” that Giuliani’s agenda may have included efforts to “prompt Ukrainians” to investigate former Vice President Joe Biden and his son hunter and engage Ukrainians in the presidential campaign, according to his opening statement, which was obtained by CNN before the deposition.

“Based on the direction of the President, we were faced with a choice: we could abandon the goal of a white house meeting for President Zelensky, which, for those reasons, we believed was crucial to strengthening U.S.-Ukrainian ties and advancing longstanding U.S. foreign policy goals in the region; or we could do as President trump directed and talk to Mr. Giuliani to address the President’s concerns,” Sondland said in his opening remarks.

“We chose the last path that seemed to all of us – Secretary (Rick) Perry, Ambassador (Kurt) Volcker, and I – to be the best alternative,” Sondland continued. “But I didn’t realize, much later, that Mr. Giuliani’s agenda could also include trying to encourage Ukrainians to investigate Vice President Biden or his son or to involve Ukrainians, directly or indirectly, in the President’s 2020 re-election campaign.”

Sondland’s testimony Thursday comes as he is under fire for his role in a July 25 phone call between trump and Zelensky in which trump repeatedly urged Zelensky to launch an investigation into the Bidens. Sondland’s testimony is likely to heighten Democrats ‘ focus on the concerns senior officials have expressed about Giuliani’s involvement in Ukraine and how they disagree with trump’s insistence on using his private lawyer to negotiate diplomatic efforts.

Text messages of Sandland with a senior us diplomat to Ukraine bill Taylor are the key point for investigation of impeachment, in which Sandland Taylor said that after talking with trump there had been “no KVI-of proquo”.

Sondland’s testimony says he was unaware of any agreement to tie U.S. security assistance with Ukraine to the Biden investigation, but also that it would be wrong.

“Let me be clear: Inviting a foreign government to conduct investigations to influence the upcoming U.S. election would be wrong,” Sondland said, according to the statement. Withholding foreign aid to pressure a foreign government into taking such steps would be wrong. I did not participate and will never participate in such endeavors. In my opinion, assistance to Ukraine is in our vital national interests and should not have been delayed for any reason.”

Sondland is a key figure from the texts of Ukraine

Sondland said he had only spoken to Giuliani briefly this year and that he was unaware that trump had raised the Biden investigation with Zelensky on the July 25 call until the transcript was released last month.

“I wasn’t on that July 25, 2019 call, and I didn’t see the transcript of that call until September 25, 2019, when the White house publicly released it,” Sondland said. “In none of the brief and General summary that I received, there was no mention Burise or former Vice-President Biden, and not even spoke about the fact that the President is trump approached with any request of the President Zelensky”.

Giuliani, however, publicly discussed in the media his efforts to investigate Biden and Ukraine this spring, which included a campaign to oust then-U.S. Ambassador to Ukraine Marie Iovanovich, whom Giuliani accused of criticizing the President. There was no evidence of wrongdoing by Joe or hunter Biden in Ukraine.

Sondland, a major donor and former Trump hotel chain owner, has been at the heart of the Democratic impeachment inquiry led by the House Intelligence, Foreign Affairs and Oversight Committees because of his appearance on text messages provided to Congress between US diplomats, high-ranking Ukrainian political assistant and Giuliani.

In texts between Sondland and Volcker that Volcker provided to Congress, a potential meeting between Zelensky and trump involved Ukraine launching an investigation before trump and Zelensky’s call, and then with Zelensky announcing the investigation Publicly.

Sondland tells Volcker that trump wanted to “get” ahead of the scheduled meeting, which he said in his testimony was a reference to Ambassador Volcker’s “efforts to encourage the Ukrainian government to adopt a public statement outlining its reform priorities.”

But he also plans to testify that Giuliani told diplomats that the statement needed two investigations “is important to the President.”

“Mr. Giuliani stressed that the President wanted a public statement by President Zelensky obliging Ukraine to study anti – corruption issues,” Sondland said. “Mr. Giuliani specifically mentioned the 2016 election (including the DNC server) and Burisma as two anti-corruption investigation topics important to the President.”

A few weeks later, Taylor expressed concern that the suspension of U.S. aid to Ukraine was related to the investigation. “As I said on the phone, I think it’s crazy to withhold security assistance to aid a political campaign,” Taylor writes to Sondland on September 9, prompting Sondland to respond that Taylor was wrong and that “the President was crystal clear, not a quid Pro quo of any kind.”

Speaking about his concern that Ukrainians might perceive the connection, Sondland told lawmakers that he responded to Taylor after he called the President directly to ask for help for Ukraine.

“I asked the President:” What do you want from Ukraine?”The President said,” Nothing. There is no qui-Pro-quo, ” Sondland said. “The President reiterated: “there is no quid pro quo” several times. It was a very short call. And I remember the President was in a bad mood.”

In his prepared statement, Sondland joined career diplomats and handed responsibility for his role in the situation to political players, including trump and Secretary of state Mike Pompeo.

Sondland also said Pompeo, another potentially key player in Ukraine who has so far refused to turn over documents to hill, was aware of all his efforts on Ukraine policy and put him to work for the country from day one. Ukraine, of course, will not be the responsibility of the us European Union expert, as it is not a member, say critics of Sondland. On Thursday, Sondland countered that the conflicts in Ukraine, especially over the Crimean Peninsula, are major security crises for Europe and the United States.

“I understand that all my actions with the participation of Ukraine were blessed by Secretary Pompeo, as my work corresponded to the long-standing foreign policy goals of the United States. Indeed, just recently, Secretary Pompeo sent me a congratulatory note about me doing a great job, and he encouraged me to keep knocking away, ” Sondland said, according to his prepared statement.

Sondland also told lawmakers that he was unaware of any concern among top national security Council officials regarding his efforts and in planning the July 25 challenge contrary to what former trump adviser Fiona hill told House committees earlier this week when she revealed then-national security adviser John Bolton said the operation conducted by Sondland and acting chief of staff Mick Mulvaney was like ” drug trafficking.”

“But if Ambassador Bolton, Dr. hill or others harbored any concerns about the correctness of what we were doing, they never shared those concerns with me, then or later,” he said.

Notably, Sondland expressed his support for the Ukrainian Ambassador, who was attacked by Giuliani and fired by trump and whose removal has been a sore point for career state Department officials who have testified in the impeachment investigation so far.

“I found her a great diplomat, “Sondland said, adding,”I was never part of any campaign to knock her out or knock her out, and I regretted her departure.”

Sondland told the Committee Thursday that he did not turn over any documents because the State Department told him the documents were confidential to the Executive branch or privileged. The white house supported the view that Sondland himself could not turn them over. Sondland’s lawyers say he urged the state Department to make the documents available.

Documents relevant to Sondland’s testimony, according to a source familiar with the matter, include sondland’s communications with hill and the national security Council, emails and briefing materials appointing him for Ukraine at the start of his term, Volcker’s introduction of Giuliani and Sondland, and a July letter between Volcker, Taylor and Sondland saying Zelensky should stay out of the 2020 U.S. presidential campaign.

This story was updated with additional events Thursday.