WASHINGTON – Secretary of State Mike Pompeo’s name isn’t mentioned in the explosive whistleblower complaint that alleges President Donald Trump used the power of his office to press a foreign government for damaging information about a top political rival.

And the nation’s top diplomat insisted on Thursday that State Department officials had acted appropriately in their dealings with Ukraine’s new government, led by President Volodymyr Zelensky.

But Pompeo – one of Trump’s most trusted advisers and his former CIA chief – was almost certainly briefed on the controversial Trump-Zelensky phone call that prompted an intelligence officer to file the whistleblower complaint and House Democrats to launch an impeachment inquiry.

Pompeo is now under growing scrutiny from Democrats in Congress, who have demanded information about the State Department’s alleged role in arranging conversations between Ukrainian officials and Rudy Giuliani, Trump’s personal lawyer. House Democrats on Friday subpoenaed Pompeo for documents related to Giuliani and Ukraine, and a top Senate Democrat also demanded information about Pompeo's role in the scandal.

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On Thursday, Giuliani posted a text message on Twitter that appeared to be from the State Department’s special envoy for Ukraine, Kurt Volker, connecting the former New York mayor to Andriy Yermak, a top aide to Zelensky.

“As discussed, connecting you here with Andrey Yermak, who is very close to President Zelensky,” the July 19 text message reads, using an alternative spelling for Yermak's first name. “I suggest we schedule a call together on Monday – maybe 10 am or 11 am Washington time?”

Volker resigned on Friday.

Earlier this week, Giuliani said he only contacted Ukrainian officials at the urging of the State Department.

“I never talked to a Ukrainian official until the State Department called me and asked me to do it,” Giuliani told Fox News on Tuesday. “And then I reported to every conversation back to them.”

For months, Giuliani has been pressing the Ukrainians for damaging information on former Vice President Joe Biden and his son, Hunter Biden, whose sat on the board of a Ukrainian energy company when Biden was Obama’s No. 2. Trump and Giuliani have alleged wrongdoing by the Bidens, but they have not produced any evidence of impropriety.

Hunter Biden:Who is former Vice President Joe Biden's son mentioned in Ukraine-Trump call?

Volker, who serves in the unpaid position on a part-time basis, did not respond to an email seeking comment, nor did the State Department’s press office. Giuliani did not respond to a voicemail and text messages from USA TODAY.

Democrats were flabbergasted by Giuliani’s Twitter revelations seeming to show Volker's involvement.

“This isn’t real, is it? Giuliani didn’t just voluntarily expose a highly illegal coordination between the Trump campaign and the State Department?” Sen. Chris Murphy, a Democrat from Connecticut who sits on the Foreign Relations Committee, tweeted in response to Giuliani’s post.

Michael McFaul, a former U.S. ambassador to Russia under President Barack Obama, called it “outrageously inappropriate” for Trump’s personal lawyer to be engaging with foreign officials on what amounted to a campaign issue and for the State Department to be facilitating such interactions.

On Friday, House Democrats sent a subpoena to Pompeo demanding documents related to the State Department's interactions with Giuliani and with Ukrainian officials.

"Your failure or refusal to comply with the subpoena shall constitute evidence of obstruction of the House’s impeachment inquiry,” Rep. Eliot Engel, the chairman of the Foreign Affairs Committee, wrote in a letter with two other committee chairmen involved in the impeachment inquiry.

Engel, D-N.Y., said he had also notified Pompeo that the three committees had scheduled depositions for five State Department employees, including Volker.

More:Public opinion on Trump impeachment may be shifting as more Ukraine details emerge

According to whistleblower complaint, Volker and another U.S. ambassador, Gordon Sondland, had met with Giuliani to try to "contain the damage" his efforts were having on U.S. national security. The whistleblower said Volker and Sondland also met with Ukrainian officials to help them navigate the "differing messages" they were getting through official U.S. government channels and Giuliani's private outreach.

At a news conference Thursday, Pompeo did not directly answer a question about whether the State Department instructed Giuliani to reach out to Ukrainian officials on Trump’s behalf.

More:Former Ukrainian prosecutor: I'm not aware of 'any possible violation of Ukrainian law' by the Bidens

“Here’s what I’ll say this morning about the engagement of the State Department,” Pompeo told reporters. “To the best of my knowledge, so from what I’ve seen so far, each of the actions that were undertaken by State Department officials was entirely appropriate and consistent with the objective that we’ve had certainly since this new government has come into office."

Pompeo also sidestepped a question last week about whether he pressed Ukraine’s foreign minister, during a September phone call, to open an investigation into the Bidens. Pompeo offered a only vague account of that conversation.

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According to the whistleblower's account, the State Department's top counselor, T. Ulrich Brechbuhl, was listening in on Trump's July 25 call with Zelensky. In that conversation, Trump asked Zelensky for a "favor," pressing him to open an investigation of Biden, according to a summary released by the White House.

Brechbuhl would have briefed Pompeo "immediately" on the conversation, said Aaron David Miller, a senior fellow at the Carnegie Endowment for International Peace who has served as a State Department adviser in Republican and Democratic administrations.

The question, Miller said, is what did Pompeo do once he learned the details of Trump's remarks. On moral and ethical grounds, Miller said, Pompeo should have gone to Trump and said: "Mr. President, the implications of what you’ve done are devastating, both to American foreign policy and prospectively to your own interests. You may have broken the law."

Miller said there's no way to know, based on the evidence that has emerged so far, how Pompeo handled the situation. But he noted that Pompeo is himself a politician, with his own ambitions, and he has become one of Trump's closest advisers.

"Pompeo was probably very reluctant to get in the middle of this," Miller said. "The circumstantial evidence would suggest that Pompeo was not prepared to confront the president" and was similarly unable or unwilling to stop Giuliani's outreach to the Ukrainians.

Engel, the House Foreign Affairs Committee chairman, said he's concerned that Trump appointees at the State Department are "deeply entangled in this scandal.”

Sen. Bob Menendez, D-N.J., the top Democrat on the Foreign Relations Committee, has also called on Pompeo to explain what actions he and other State Department employees took to help Trump and Giuliani press Ukraine for damaging information about Biden.

“As Secretary of State, you are charged with carrying out foreign policy for the United States,” Menendez wrote in a letter to Pompeo on Friday. “Yet it appears that our policy with Ukraine was effectively outsourced to a private individual pursuing the personal vendettas of the president.”

The State Department press office did not respond to a request for comment on Menendez’ letter.

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