By Michael D. Shear and Peter Baker, New York Times–

The Ukrainians may have learned about the hold on aid much earlier than previously known.

Ukraine officials may have been aware that security aid was cut off by July 25 — much earlier than previously known and the same day that President Trump talked on the phone with the president of Ukraine, a top Pentagon official said Wednesday.

Laura K. Cooper, the deputy assistant secretary of defense for Russia, Ukraine and Eurasia, said that she was aware of multiple communications between Ukrainian Embassy officials and members of her staff in which the embassy officials asked questions about delivery of the security aid to their country.

Ms. Cooper said that a member of her staff received a question about the aid on July 25 from the Ukrainian Embassy, which asked “what was going on with Ukraine assistance.” She said that during the week of Aug. 6, other members of her staff saw officials from the embassy who raised the issue of the aid.

The timing of when Ukraine knew that the aid had been frozen is a critical question as Democrats build a case that Mr. Trump tried to leverage the aid for a public announcement of investigations into his political rivals. The security aid was frozen in early July, and Republicans have insisted that Ukraine did not know about the hold until it was reported by a news outlet on Aug. 28.

Mr. Trump’s allies have also said that Mr. Trump could not have coerced Volodymyr Zelensky, the president of Ukraine, during the July 25 call because Mr. Zelensky did not know at the time that the aid was held up. The new information from Ms. Cooper could undercut the Republican efforts to defend the president.

Ms. Cooper said her staff recalled the issue of concerns about Ukraine’s security aid coming up with members of the Ukrainian Embassy in other meetings during the month of August, though they could not recall precisely when those meetings took place.

“They believe the question of the hold came up at some point,” Ms. Cooper said.

She also cited several emails dated July 25 between members of her staff and State Department officials in which the diplomats wrote that the Ukrainian Embassy knew about the hold on the security assistance. Ms. Cooper said she did not believe she was shown the emails at the time.

Ms. Cooper said she learned of the new information about the inquiries from Ukrainian officials after members of her staff saw the transcript of her earlier, closed-door testimony when it was released to the public on Nov. 11, and brought new details of the timeline to her attention.

David Hale, the State Department’s No. 3 official, also fielded questions about the hold on security aid to Ukraine and the attacks by Rudolph W. Giuliani, President Trump’s personal lawyer, on the reputation of Marie L. Yovanovitch, the United States ambassador to Ukraine. She was eventually recalled from her post.

Mr. Hale told lawmakers that what happened to Ms. Yovanovitch was “wrong” and that “I believe that she should have been able to stay at post and continue to do the outstanding work.”

Sondland testified he worked with Giuliani to pressure Ukraine ‘at the express direction of the president.’

Mr. Sondland told the committee that he and other advisers to Mr. Trump pressured Ukraine to investigate Democrats “because the president directed us to do so.”

Mr. Sondland said that he, Energy Secretary Rick Perry and Kurt D. Volker, the special envoy for Ukraine, were reluctant to work with Mr. Giuliani on the pressure campaign and agreed only at Mr. Trump’s insistence.

“Secretary Perry, Ambassador Volker and I worked with Mr. Rudy Giuliani on Ukraine matters at the express direction of the president of the United States,” Mr. Sondland told the committee. “We did not want to work with Mr. Giuliani. Simply put, we were playing the hand we were dealt.” With no alternative, he said, “we followed the president’s orders.”

Mr. Sondland confirmed what has already been known, that there was a clear “quid pro quo” linking a coveted White House meeting for Ukraine’s president to the investigations Mr. Trump wanted. And he said he was concerned about “a potential quid pro quo” linking $391 million in security aid that Mr. Trump suspended to the investigations he desired.

But under questioning, Mr. Sondland acknowledged that Mr. Trump never told him that. “I never heard from President Trump that aid was conditioned on an announcement of investigations,” he testified.

And he was asked by Republicans to repeat a conversation he had with Mr. Trump that he has previously described in which he asked the president what he wanted from Ukraine. “It was a very short, abrupt conversation,” Mr. Sondland said. “He was not in a good mood. And he just said, ‘I want nothing. I want nothing. I want no quid pro quo. Tell Zelensky to do the right thing.’”

The conversation took place after the White House had already learned a whistle-blower had come forward with a complaint alleging that the president was abusing his power to try to enlist Ukraine to interfere on his behalf in the 2020 election.

Mr. Giuliani challenged Mr. Sondland in a tweet, saying the ambassador was “speculating based on VERY little contact. I never met him and had very few calls with him, mostly with Volker. Volker testified I answered their questions and described them as my opinions, NOT demands. I.E. no quid pro quo.”

He later deleted the tweet.

Mr. Perry also took issue with Mr. Sondland, issuing a statement through his department saying that the testimony “misrepresented both Secretary Perry’s interaction with Rudy Giuliani and direction the secretary received from President Trump.”

The statement said Mr. Perry spoke with Mr. Giuliani only once. “At no point before, during or after that phone call did the words ‘Biden’ or ‘Burisma’ ever come up in the presence of Secretary Perry,” the statement said.

‘Everyone was in the loop,’ Sondland said, including Pence, Pompeo, Mulvaney and others.

Mr. Sondland testified that he told Vice President Mike Pence in late August that he feared the military aid withheld from Ukraine was tied to the investigations Mr. Trump sought and that he kept Secretary of State Mike Pompeo apprised of his efforts to pressure Ukraine.

The revelations suggested that Mr. Sondland has decided to publicly implicate the senior-most members of Mr. Trump’s administration in the matter, including Mick Mulvaney, the acting White House chief of staff, and he provided a series of text messages and emails to buttress his account.

“Everyone was in the loop,” he said told the committee. “It was no secret.”

If other officials were concerned that he was doing something wrong, as testimony now indicates, Mr. Sondland said they did not tell him at the time. “Everyone’s hair was on fire,” he said, “but no one decided to talk to us.”

The striking account — a major departure from Mr. Sondland’s initial closed-door testimony in the impeachment inquiry last month — also indicated that the ambassador who played a central role in the pressure campaign was eager to demonstrate that he did so only reluctantly with the knowledge and approval of the president and top members of his team.

Mr. Sondland rejected the notion that he was part of an illicit shadow foreign policy that worked around the normal national security process. “The suggestion that we were engaged in some irregular or rogue diplomacy is absolutely false,” he said, pointing to messages and phone calls in which he kept the White House and State Department informed of his actions. He added: “Any claim that I somehow muscled my way into the Ukraine relationship is simply false.”

The ambassador said that he “mentioned to Vice President Pence before the meetings with the Ukrainians that I had concerns that the delay in aid had become tied to the issue of investigations.” He testified that the conversation occurred shortly before Mr. Pence met with President Volodymyr Zelensky of Ukraine while they were in Warsaw.

At that meeting, Mr. Zelensky brought up the issue of the withheld aid and Mr. Pence said he would discuss the matter with Mr. Trump. Afterward, Mr. Sondland said he informed Andriy Yermak, a top Ukrainian official, that the money would probably not flow without Mr. Zelensky making a public commitment to the investigations.

Marc Short, Mr. Pence’s chief of staff, issued a statement after his testimony denying Mr. Sondland’s account.

“The vice president never had a conversation with Gordon Sondland about investigating the Bidens, Burisma, or the conditional release of financial aid to Ukraine based upon potential investigations,” Mr. Short said. “This alleged discussion recalled by Ambassador Sondland never happened.”

Mr. Sondland also said that “even as late as September,” after the pressure campaign emerged in the news media, “Secretary Pompeo was directing Kurt Volker to speak with Mr. Giuliani.”

In a statement issued from Mr. Pompeo’s plane as he returned to Washington from Brussels, his spokeswoman denied something that Mr. Sondland never testified to.

“Gordon Sondland never told Secretary Pompeo that he believed the president was linking aid to investigations of political opponents,” Morgan Ortagus, the State Department spokeswoman, said in the statement. “Any suggestion to the contrary is flat out false.”

Trump dismissed Sondland, saying ‘I don’t know him very well.’

President Trump distanced himself from Gordon D. Sondland, a top donor he appointed as ambassador to the European Union, after the diplomat told lawmakers that he and other advisers pressured Ukraine to investigate Democrats at the president’s “express direction.”

As he headed to Marine One to depart on a trip to Texas, Mr. Trump stopped to talk with reporters briefly and pointed out that Mr. Sondland had testified that the president had told him at one point that he wanted nothing from Ukraine and there was no quid pro quo.

“That means it’s all over,” Mr. Trump said, shouting over the roar of helicopter rotors and reading from handwritten notes scrawled out in large block letters. “This is the final word from the president of the United States: ‘I want nothing.’”

In a tweet later Wednesday afternoon, Mr. Trump declared the “impeachment witch hunt” to be over, quoting Mr. Sondland’s testimony in all caps.

The president’s press secretary, Stephanie Grisham, later issued a statement emphasizing those points. “Ambassador Sondland’s testimony made clear that in one of the few brief phone calls he had with President Trump, the president clearly stated that he ‘wanted nothing’ from Ukraine and repeated ‘no quid pro quo over and over again,’” she said.

Despite that, Mr. Sondland told the House Intelligence Committee on the fourth day of public impeachment hearings that it was clear to him that the president was intently interested in having the Ukrainians publicly commit to investigating Democrats, including former Vice President Joseph R. Biden Jr., whose son served on the board of the Ukrainian energy company Burisma.

Mr. Trump often disavows knowing advisers once they become problematic for him. Just last month, Mr. Trump called Mr. Sondland, who gave the president’s inaugural fund $1 million, “a really good man and great American.”

But on Wednesday he said: “I don’t know him very well. I have not spoken to him much. This is not a man I know well. He seems like a nice guy though.” Ms. Grisham’s statement amplified that by referring to “the few brief phone calls” she said the two men have had.

Mr. Sondland portrayed their relationship differently, describing it as a chummy one that ranged even beyond the issues at hand. “I’ve had a lot of conversations with the president about completely unrelated matters that have nothing to do with Ukraine,” he said. Their conversations, he testified, featured, “a lot of four-letter words.”

Democrats argued that Sondland’s testimony bolstered their case for impeaching Trump.

After Mr. Sondland testified that everyone from Mr. Trump on down was aware of the pressure campaign on Ukraine, House Democrats quickly declared that he had bolstered their case for impeachment.

Representative Adam B. Schiff, Democrat of California and chairman of the House Intelligence Committee, called Mr. Sondland’s testimony “among the most significant evidence to date,” saying he described “a basic quid pro quo” that conditioned American security aid on Ukraine agreeing to investigate Mr. Trump’s political rivals.

Mr. Schiff mocked Republican attempts to undermine Mr. Sondland’s testimony, saying that his colleagues on the Intelligence Committee “seem to be under impression that unless the president spoke the words, ‘Ambassador Sondland, I am bribing the Ukrainian president,’ that there’s no evidence of bribery. If he didn’t say, ‘Ambassador Sondland, I’m telling you I’m not going to give the aid unless they do this,’ that there’s no evidence of a quid pro quo.”

“Nonetheless,” Mr. Schiff said, “you have given us a lot of evidence of precisely that conditionality.”

Republicans scoffed. Representative Mike Turner, Republican of Ohio, pressed Mr. Sondland to acknowledge that he was never explicitly told that Ukraine’s military aid was tied to the investigations that Mr. Trump wanted.

“No one told you? Not just the president — Giuliani didn’t tell you, Mulvaney didn’t tell you, nobody,” Mr. Turner said. “Pompeo didn’t tell you?

“No one on this planet told you that President Trump was tying aid to investigations,” Mr. Turner added. “Yes or no?”

“Yes,” Mr. Sondland answered.

For Trump, what mattered most was that investigations of Democrats be publicly announced.

Under questioning, Mr. Sondland put his finger on a distinction that often gets overlooked in the discussion of Mr. Trump’s interest in Ukraine: For the president, it seemed more important that Ukrainian officials announce that they were investigating Democrats than for them to actually follow through.

“I never heard, Mr. Goldman, anyone say that the investigations had to start or had to be completed,” Mr. Sondland told Daniel S. Goldman, the top Democratic counsel who questioned him. “The only thing I heard from Mr. Giuliani or otherwise was that they had to be announced in some form and that form kept changing.”

The distinction is important because Democrats are arguing that Mr. Trump was not trying to fight corruption, but instead trying to enlist a foreign power to discredit his rivals in a way that would benefit him in the 2020 election. In pressing Mr. Sondland on the matter, Mr. Goldman noted that, “there would be political benefits to a public announcement.”

Mr. Sondland responded, “The way it was expressed to me was that the Ukrainians had a long history of committing to things privately and then never following through, so President Trump, presumably, again communicated through Mr. Giuliani, wanted the Ukrainians on record publicly that they were going to do these investigations.”

“But you never heard anyone say that they really wanted them to do the investigations, just that they wanted to announce” them, Mr. Goldman said.

“I didn’t hear either way,” Mr. Sondland said. “I didn’t hear either way.”

Sondland confirmed an indiscreet conversation with Trump but disputed descriptions of July 10 meeting.

Mr. Sondland in his prepared testimony confirmed a conversation with Mr. Trump at a key moment in the timeline that he did not volunteer during his original testimony. But he disputed descriptions by other witnesses of another key meeting.

Mr. Sondland did not challenge the account of a lunch meeting on the outdoor patio of a Kyiv restaurant on July 26, the day after Mr. Trump’s phone call with Mr. Zelensky. David Holmes, the political counselor at the American Embassy in Ukraine, told investigators that he overheard Mr. Trump and Mr. Sondland talking on the phone.

“So, he’s going to do the investigation?” Mr. Trump asked, according to Mr. Holmes. Mr. Sondland told him yes. Mr. Zelensky “loves your a**” and would do “anything you ask him to,” Mr. Sondland said, according to Mr. Holmes’s statement.

But in his testimony Wednesday, Mr. Sondland also denied that a July 10 meeting at the White House with Ukrainian officials turned sharply tense, as others have testified in recent days.

Fiona Hill, then the senior director for Europe and Russia at the National Security Council, and her deputy for Ukraine policy, Lt. Col. Alexander S. Vindman, previously told lawmakers that the meeting led to a confrontation over Mr. Sondland’s unconventional role in Ukraine policy.

Mr. Sondland said he did not remember that.

“Their recollections of those events simply don’t square with my own or with those of Ambassador Volker or Secretary Perry,” he said in his prepared testimony.

Emily Cochrane contributed reporting.