Secretary of State Mike Pompeo said Saturday that he had responded to the House committees seeking documents in their impeachment inquiry of President Trump, but congressional investigators say they are still waiting for Pompeo to comply with their subpoena.

Also, Gordon Sondland, the U.S. ambassador to the European Union ensnared in the impeachment inquiry of President Trump, has agreed to meet behind closed doors Tuesday with the three panels — Intelligence, Foreign Affairs and House Oversight — spearheading the probe, according to a committee aide. On Saturday, the official confirmed the schedule on the condition of anonymity to discuss private deliberations.

NBC News first reported Sondland’s planned appearance.

At a news conference with the foreign minister of Greece, Pompeo said he had sent a letter to Capitol Hill as “our initial response to the document request. We’ll obviously do all the things we’re required to do by law.”

His remarks came as Democratic-led House committees leading the impeachment investigation said that Pompeo failed to meet a Friday deadline to deliver subpoenaed State Department documents to them. “However, the State Department has contacted the committees on this matter, and we hope the Department will cooperate in full promptly,” a committee official said.

Pompeo repeated charges made a week ago that those leading the congressional inquiries have “harassed and abused State Department employees” by contacting them directly and failing to go through proper channels to request testimony and documents.

“I remember once, when I was on that side and we were looking for documents, I remember precisely how long it took for those documents to come across,” said Pompeo, a former House member from Kansas who, while in the majority, helped lead the Republican investigation of the Clinton-led State Departments actions in Benghazi, Libya after a 2012 terrorist attack killed four American officials.

The secretary of state, who has been on a week-long trip to southern Europe, has been relatively closed-lipped about the impeachment inquiry unfolding in Washington, dismissing questions about it as political gamesmanship and a “silly gotcha game.” He is due to return to Washington on Sunday.

Pompeo also defended Trump’s decision to ask Ukraine and China to investigate former vice president Joe Biden and his son Hunter, who served on the board of a major Ukrainian energy company.

Hunter Biden served for nearly five years on the board of Burisma, Ukraine’s largest private gas company, whose owner came under scrutiny by Ukrainian prosecutors for possible abuse of power and unlawful enrichment. Hunter Biden was not accused of any wrongdoing in the investigation. As vice president, Joe Biden pressured Ukraine to fire the top prosecutor, Viktor Shokin, who Biden and other Western officials said was not sufficiently pursuing corruption cases. At the time, the investigation into Burisma was dormant, according to former Ukrainian and U.S. officials.

Pompeo said it was “very reasonable” and “our duty” to ask other governments to help investigate interference in the 2016 U.S. election, as Trump has. “There’s been some suggestion somehow that it would be inappropriate for the United States government to engage in that activity, and I see it as just precisely the opposite, Pompeo said. “I see our duty to engage in activity that ensures that we have fair, free elections.”

Asked later whether other countries, including Greece, could come under pressure based on their willingness to help the U.S. president, Pompeo laughed.

“It’s totally appropriate, right, isn’t that right? Yes, it’s totally right. . . . “Nations do this, nations work together and they say ‘Boy, goodness gracious, if you can help me with X and we’ll help you achieve Y.’ This is what partnerships do,” Pompeo said. “It’s win-win. It’s better for each of us.”

A whistleblower’s complaint revealed a July 25 call in which Trump pressed Ukrainian President Volodymyr Zelensky to investigate the activities of Biden, a 2020 Democratic presidential candidate, and his son and subsequent efforts to restrict access to records of the call. It also alleged that Trump asked Zelensky to look into unproven allegations that Russia’s interference in the 2016 U.S. presidential election originated in Ukraine.

Trump again maligned the whistleblower, Democrats and the news media in tweets Saturday morning, baselessly calling the New York Times and The Washington Post “pure fiction.”

“The so-called Whistleblower’s account of my perfect phone call is “way off,” not even close. (Rep. Adam) Schiff and (Speaker Nancy) Pelosi never thought I would release the transcript of the call. Got them by surprise, they got caught. This is a fraud against the American people!” Trump tweeted.

Meanwhile, the role of Energy Secretary Rick Perry in the controversy over Trump’s call with Zelensky is likely to get increased scrutiny.

In a phone call with House Republicans on Friday, according to three federal officials familiar with the matter who spoke on the condition of anonymity to describe Trump’s private remarks, Trump emphasized that he had made the July 25 call with the Ukrainian president at the request of Perry. Trump said Perry urged him to contact Zelensky to discuss a liquefied natural gas project, these officials said.

Asked about the president’s comments, which were first reported by Axios, Energy Department spokeswoman Shaylyn Hynes said in an email that Perry “absolutely supported and encouraged the President to speak to the new President of Ukraine to discuss matters related to their energy security and economic development.”

“He continues to believe that there is significant need for improved regional energy security,” Hynes added, “which is exactly why he is heading to Lithuania tonight to meet with nearly two dozen European energy leaders (including Ukraine) on these issues.”

It’s unclear, however, what Perry’s request had to do with Trump deciding to bring up the political investigations with Zelensky.

In the rough transcript of the call released by the White House last week, Trump made no mention to Zelensky of any liquefied natural gas projects. Zelensky at one point mentions that “there is much potential for our two countries and one of the issues that is very important for Ukraine is energy Independence,” but Trump does not follow up on the comment.

On Thursday, The Washington Post and Politico reported that Perry plans to step down from his post by the end of the year.

As part of their investigation, Democrats also subpoenaed the White House for documents on Friday, a step they had announced earlier in the week, and demanded documents from Vice President Pence.

“During a press conference on Wednesday, President Trump was asked if he would cooperate with the House impeachment inquiry. He responded, ‘I always cooperate.’ President Trump’s claim is patently false,” the three committee chairmen wrote. “The White House has refused to engage with — or even respond to — multiple requests for documents from our Committees on a voluntary basis. After nearly a month of stonewalling, it appears clear that the President has chosen the path of defiance, obstruction, and cover-up.”

The three chairmen are Reps. Adam B. Schiff (D-Calif.) of the Intelligence Committee, Eliot L. Engel (D-N.Y.) of the Foreign Affairs Committee and Elijah E. Cummings (D-Md.) of the Oversight and Reform Committee.

In a Saturday morning tweet, Trump called the whistleblower’s account “a fraud against the American people!”

Sondland, who will give his deposition in the coming week, worked behind the scenes to carry out Trump’s wishes in a country that’s not part of the European Union. The ambassador met with Zelensky to give “advice” about how to “navigate” Trump’s demands, the whistleblower reported. And in text messages turned over to House investigators Thursday, Sondland insisted that Trump’s decision to withhold nearly $400 million in military aid to Ukraine was not a quid pro quo — as diplomat William B. “Bill” Taylor had feared, according to the texts.

“Bill, I believe you are incorrect about President Trump’s intentions,” Sondland wrote last month, before urging Taylor, the U.S. chargé d’affaires in Ukraine, to call him instead.

Kurt Volker, the former U.S. envoy to Ukraine, spent almost 10 hours behind closed doors Thursday with the committees, providing a deposition and text messages.

Unlike Volker, who turned all his communications over to Congress, Sondland transmitted his texts and documents to the State Department, which means the committees will have to fight the agency for access to them.

Greg Miller, Juliet Eilperin, Rachael Bade and Josh Dawsey contributed to this report.