Secretary of State Mike Pompeo made at least four misleading statements in recent days about his knowledge of the contents of a whistleblower's complaint about a phone call between President Donald Trump and Ukrainian President Volodymyr Zelensky.

Pompeo was unequivocal at first that because he hadn't seen the complaint, he couldn't comment on the substance of the call.

But it eventually surfaced that Pompeo was a direct participant in the phone call, a revelation that raised new questions about his earlier denials, as well as his assertions that neither he, nor other State Department employees, did anything wrong.

Pompeo's role isn't limited to his involvement in the call; the State Department's inspector general, Steve Linick, requested an "urgent" briefing on Capitol Hill this week to "discuss and provide staff with copies of documents related to the State Department and Ukraine."

PBS NewsHour reported shortly before Linick's testimony on Wednesday that it would center around "retaliation against State Department officials who are trying to cooperate with House Democrats."

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Secretary of State Mike Pompeo was unequivocal: He hadn't seen a whistleblower's complaint about a July phone call President Donald Trump had with Ukrainian President Volodymyr Zelensky, so he couldn't comment on the content of the conversation.

But Pompeo left out a critical detail: He was a participant in the conversation.

"I was on the phone call," Pompeo confirmed on Wednesday during a news conference in Rome after The Wall Street Journal on Tuesday first reported on his involvement.

The stunning acknowledgement raised immediate questions about Pompeo's previous comments on the matter, in which he repeatedly dodged inquiries about his knowledge of Trump's request for Ukraine to investigate former Vice President Joe Biden and his son.

Pompeo appears to have made at least four significantly misleading statements about his involvement in the call, The Washington Post's Philip Bump said on Wednesday.

Read more: The Trump whistleblower told the House Intelligence Committee about their concerns before filing an official complaint

"You say you know nothing about this, but let me ask you this question," the ABC News host Martha Raddatz asked Pompeo during a September 22 interview. "The Ukrainian presidential readout of the conversation said they discussed, quote, 'investigation of corruption cases which inhibited the interaction between Ukraine and the USA.'"

"The president tweeted Saturday: 'It was a perfectly fine and respectful conversation,'" Raddatz added. "Do you think it's, quote, 'perfectly fine' to ask a foreign leader to investigate a political opponent?"

"I think I saw a statement from the Ukrainian foreign minister yesterday, said there was no pressure applied in the course of the conversation," Pompeo said.

He didn't mention that he'd been witness to the president's conversation.

Earlier, when Raddatz asked him about recent reporting that Trump pressed Zelensky eight times during the call to work with his personal lawyer Rudy Giuliani to investigate Biden's son, Pompeo again sidestepped the question and pivoted to the whistleblower's complaint.

"So you just gave me a report about a IC whistleblower complaint, none of which I've seen," he said, again failing to mention his central role in the matter at the heart of the complaint.

Raddatz later asked Pompeo that if the conversation were "perfectly fine," as Trump said, "why not release the transcript or a portion to the public?"

Pompeo punted the question to the White House, saying they would "have to explain."

"We don't release transcripts very often. It's the rare case," he said. "Those are private conversations between world leaders. And it wouldn't be appropriate to do so, except in the most extreme circumstances. There's no evidence that that would be appropriate here at this point."

Read more: Another whistleblower has come forward, this time alleging 'inappropriate efforts' to influence Trump's tax audit

The secretary of state was grilled again about the State Department's involvement in the Ukraine controversy on September 26 after the White House released a summary of the call.

A reporter pointed out to Pompeo that Giuliani had publicly said the State Department asked him to get involved with Ukraine and reach out to Zelensky and his advisers: "If so, what exactly was he told to do by the State Department, by whom? And just more broadly, the whistleblower complaint does not appear to suggest any allegation of impropriety from people in the State Department. Is that correct? Are you confident that none of your staff — that you or none of your staff did anything improper in this whole situation?"

As a participant in the phone call at the center of the reporter's question, Pompeo was presumably well-positioned to shed light on his own involvement in the matter.

But he didn't, instead narrowing his answer to focus on the whistleblower's complaint, which had been released shortly before the news conference.

"I haven't had a chance to actually read the whistleblower complaint yet," Pompeo said. "I read the first couple of paragraphs and then got busy today. But I'll ultimately get a chance to see it. If I understand it right, it's from someone who had secondhand knowledge."

He failed to mention, of course, that he had firsthand knowledge of the events described in the complaint.

Read more: The White House is 'paralyzed' and 'teetering on the edge of a cliff' as it grapples with Ukraine fallout and 'Hurricane Rudy'

Pompeo's role in the controversy isn't limited to his participation in the Trump-Zelensky phone call. The secretary of state also appears to be intricately involved in efforts to prevent State Department officials from cooperating with the House of Representatives' formal impeachment inquiry into Trump.

On Tuesday, Pompeo sent a letter to the House Intelligence, Foreign Affairs, and Oversight committees, telling them their requests to depose department officials connected to the whistleblower's complaint are "not feasible" and "do not provide adequate time for the Department and its employees to prepare" for testimony.

"I'm concerned with aspects of the Committee's request that can be understood only as an attempt to intimidate, bully, & treat improperly the distinguished professionals of the Department of State, including several career FSOs," he tweeted.

He added, "Let me be clear: I will not tolerate such tactics, and I will use all means at my disposal to prevent and expose any attempts to intimidate the dedicated professionals whom I am proud to lead and serve alongside at the Department of State."

Democratic lawmakers hit back shortly after, telling Pompeo "any effort to intimidate witnesses or prevent them from talking with Congress — including State Department employees — is illegal and will constitute evidence of obstruction of the impeachment inquiry."

They also accused Pompeo of "intimidating Department witnesses" to shield himself and Trump from scrutiny. They added that Pompeo's participation in the Zelensky call made him "a fact witness in the House impeachment inquiry."

The public will likely get more details about Pompeo's alleged efforts in the near future. The State Department's inspector general, Steve Linick, on Tuesday requested an "urgent" briefing with lawmakers to "discuss and provide staff with copies of documents related to the State Department and Ukraine."

PBS NewsHour's Yamiche Alcindor reported shortly before Linick's testimony on Wednesday that it would center around "retaliation against State Department officials who are trying to cooperate with House Democrats."