© francois lenoir/Reuters

WASHINGTON—A top U.S. diplomat told House committees last week that efforts by President Trump and his allies to press Kyiv to open investigations in exchange for a White House meeting with Ukraine’s president amounted to a quid pro quo, his lawyer said.

Gordon Sondland, the U.S. ambassador to the European Union, told House committees that he believed Ukraine agreeing to open investigations into Burisma Group—a gas company where Democrat Joe Biden’s son once served on the board—and into alleged 2016 election interference was a condition for a White House meeting between Mr. Trump and Ukrainian President Volodymyr Zelensky, Mr. Sondland’s lawyer Robert Luskin said.

Asked by a lawmaker whether that arrangement was a quid pro quo, Mr. Sondland cautioned that he wasn’t a lawyer but said he believed the answer was yes, Mr. Luskin said.

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Mr. Trump has repeatedly denied the existence of a quid pro quo related to his push for Ukraine to open investigations.



Mr. Sondland was testifying as part of the impeachment inquiry, which is examining efforts by Mr. Trump and his personal lawyer, Rudy Giuliani, to push Ukraine to undertake investigations related to the Biden family and the 2016 campaign. Democrats believe the president abused the power of his office to press a foreign leader to open investigations that could benefit him politically. Mr. Trump has defended his dealings with Ukraine and decried the investigation as a “hoax.”

Mr. Sondland’s testimony has come under fresh scrutiny since the deposition earlier this week of Bill Taylor, the acting U.S. ambassador to Ukraine. Mr. Taylor’s testimony focused in part on a separate issue, telling House committees that Mr. Trump made nearly $400 million in aid contingent on the Ukrainian president investigating Mr. Biden and alleged Ukrainian interference in the 2016 U.S. election. Mr. Taylor didn’t use the term “quid pro quo” but said he understood the aid to be “conditioned” on the investigations.

Much of Mr. Taylor’s testimony suggested Mr. Sondland was aware of a separate connection between aid and investigations, which Mr. Sondland testified he wasn’t, according to his lawyer. Mr. Sondland told the committees he wasn’t involved in the decision to hold the aid to Ukraine and couldn’t independently corroborate the president’s assertions to him that the money being held up was unrelated to the push for investigations.

Some members of the House Intelligence Committee have called for Mr. Sondland to return for more questions. Rep. Will Hurd (R., Texas) in a CNN interview said Mr. Taylor’s testimony raised “a lot of questions” and that Mr. Sondland “needs to come back and answer some of these questions.”

Rep. Raja Krishnamoorthi (D., Ill.) said, “I walk away with the impression that Mr. Sondland is going to have some explaining to do.”

Lawmakers said Mr. Sondland had answered “I don’t recall” to several questions.

Mr. Sondland would likely return for more questioning if asked, Mr. Luskin said.

His testimony about perceiving a separate connection between a White House meeting and investigations runs somewhat counter to a text message he sent Mr. Taylor in September, after Mr. Taylor wrote: “I think it’s crazy to withhold security assistance for help with a political campaign.” Mr. Sondland responded, after speaking with the president: “The President has been crystal clear no quid pro quo’s of any kind.”

According to Mr. Taylor’s testimony, Mr. Sondland sought to offer a rationale for the president’s push for investigations. “Ambassador Sondland tried to explain to me that President Trump is a businessman,” Mr. Taylor said in his testimony. “When a businessman is about to sign a check to someone who owes him something, he said, the businessman asks that person to pay up before signing a check.”

Mr. Sondland, his lawyer said, doesn’t recall that particular conversation but believed the White House meeting, not the aid, was what the president wanted Ukraine to “pay up.”

Mr. Taylor testified that Mr. Sondland told him on Sept. 8 that he had spoken to Mr. Trump and that the president “was adamant that President Zelensky, himself, had to ’clear things up and do it in public,’” and that Mr. Trump insisted this wasn’t a quid pro quo.

Mr. Sondland told House committees that the president told him: “There’s no quid pro quo, but Zelensky’s got to get out there and do the right thing,” according to his lawyer. Mr. Sondland said the president didn’t specify that Mr. Zelensky needed to announce investigations into Burisma Group and the 2016 election, but that he understood that’s what the president meant given earlier conversations with Mr. Giuliani.

Mr. Taylor also recounted in his testimony that Tim Morrison, a National Security Council official, described to him a conversation Mr. Sondland had in Warsaw with a top aide to Mr. Zelensky. According to Mr. Taylor’s testimony, Mr. Sondland told the aide that the U.S. aid to Ukraine wouldn’t be released until Mr. Zelensky committed to investigating Burisma Group.

Mr. Sondland was asked about his interactions in Warsaw by the House committees and said that he doesn’t recall having that conversation with the aide to Mr. Zelensky, Mr. Luskin said.

Mr. Morrison is expected to be asked about his recollection of that conversation in testimony before the House committees next week.

Write to Rebecca Ballhaus at Rebecca.Ballhaus@wsj.com