(CNN) The chairmen of three House committees subpoenaed Secretary of State Mike Pompeo Friday over his failure to produce documents related to Ukraine.

"Pursuant to the House of Representatives' impeachment inquiry, we are hereby transmitting a subpoena that compels you to produce the documents set forth in the accompanying schedule by October 4, 2019," the chairmen of the House Foreign Affairs, Intelligence and Oversight committees wrote in a letter to Pompeo.

"The subpoenaed documents shall be part of the impeachment inquiry and shared among the Committees," wrote Reps. Adam Schiff, Eliot Engel and Elijah Cummings. "Your failure or refusal to comply with the subpoena shall constitute evidence of obstruction of the House's impeachment inquiry."

The subpoena was issued by the House Foreign Affairs Committee "after consultation with the Permanent Select Committee on Intelligence and the Committee on Oversight and Reform," according to the letter.

In addition to the subpoena, the chairmen informed the top US diplomat in a separate letter that they had scheduled depositions for five State Department officials who have been mentioned in relation to the inquiry -- Ambassador Marie "Masha" Yovanovitch , Ambassador Kurt Volker, Deputy Assistant Secretary George Kent, Counselor T. Ulrich Brechbuhl and Ambassador Gordon Sondland.

'No choice'

The Democratic chairmen wrote to Pompeo on September 9 with a request for six categories of documents "related to reported efforts by President Trump and his associates to improperly pressure the Ukrainian government to assist the President's bid for reelection."

That initial letter requested these materials by September 16. After that deadline was missed, Schiff, Engel and Cummings sent another letter on Monday warning that unless the documents were handed over, "our Committees will have no choice but to move towards compulsory process this week."

The State Department had until Thursday to reply.

While the President's personal attorney Rudy Giuliani has conducted numerous interviews all week -- including saying that he looks forward to seeing the State Department "sink themselves" as they try to create distance with him -- Pompeo has not publicly addressed the State Department's role in Giuliani's dealings with Ukraine. But last weekend, when asked about Giuliani's efforts getting himself involved in foreign affairs as he publicly calling for an investigation by the Ukrainian government into former Vice President Joe Biden, Pompeo was generally supportive.

"If there was election interference that took place by the vice president, I think the American people deserve to know," he said.

Pompeo has not publicly addressed the State Department's role in Rudy Giuliani's dealings with Ukraine. He said during a press conference on Thursday that he had not read the whistleblower complaint released earlier that day.

The secretary of state said that "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."

In August, a State Department spokesperson confirmed that Volker, at the request of Ukrainian Presidential Adviser Andriy Yermak, had "put Yermak in direct contact with Mr. Giuliani."

"Mr. Giuliani is a private citizen and acts in a personal capacity as a lawyer for President Trump. He does not speak on behalf of the U.S. Government," the spokesperson said in a statement at the time.

CNN has reached out to the State Department about the subpoena.

'All the more troubling'

In their letters to Pompeo on Friday, the chairmen said that they found Pompeo's refusal to comply with their earlier requests "all the more troubling" since "it has become clear that multiple State Department officials have direct knowledge of the subject matters of the House's impeachment inquiry."

Four of the five officials who the committee has scheduled to be deposed over the next two weeks -- Yovanovitch, the former US ambassador to Ukraine; Volker, the former US special representative for Ukraine; Brechbuhl, the counselor of the State Department; and Sondland, the US ambassador to the European Union -- were mentioned in the whistleblower complaint. The fifth -- Kent -- has overseen policy on Ukraine at the State Department since September 2018 and was previously the Deputy Chief of Mission at the US Embassy in Ukraine. Volker resigned from his role at the State Department on Friday, multiple sources confirmed to CNN.

Yovanovitch, who was unexpectedly recalled from her post in May 2019, was also mentioned in the White House rough transcript of President Donald Trump's July 25 call with Ukrainian President Volodymyr Zelensky.

"The former ambassador from the United States, the woman, was bad news and the people she was dealing with in the Ukraine were bad news so I just want to let you know that," Trump told Zelensky

During that call, Trump asks Zelensky to speak with Giuliani and suggests that the Ukrainian President "look into" Biden and his son, Hunter Biden.

"There's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the Attorney General would be great. Biden went around bragging that he stopped the prosecution so if you can look into it... It sounds horrible to me," Trump said, according to the White House transcript.

According to their complaint, the whistleblower "was told that a State Department official, Mr. T. Ulrich Brechbuhl, also listened in on the call." A State Department official has denied that Brechbuhl was on the call or briefed on it.

The whistleblower said that a day after that call, Volker and Sondland "visited Kyiv and met with President Zelenskyy and a variety of Ukrainian political figures."

"Based on multiple readouts of these meetings recounted to me by various U.S. officials, Ambassadors Volker and Sondland reportedly provided advice to the Ukrainian leadership about how to 'navigate' the demands that the President had made of Mr. Zelenskyy," they wrote.

The whistleblower also said that the "multiple U.S. officials" told them that two ambassadors were among those "had spoken with Mr. Giuliani in an attempt to 'contain the damage' to U.S. national security."

"Starting in mid-May, I heard from multiple U.S. officials that they were deeply concerned by what they viewed as Mr. Giuliani's circumvention of national security decisionmaking processes to engage with Ukrainian officials and relay messages back and forth between Kyiv and the President," the whistleblower wrote in their complaint.

Giuliani has denied the charges raised in the whistleblower complaint.

"At no time did either one of them say they wanted to contain damage," Giuliani told CNN Thursday. "At no time did the State Department in communication with me ever relay any of that information you're talking about."

Giuliani also said he had a "nice little trail" of text message conversations with Volker to prove his story. He shared one of those alleged messages with CNN and on Twitter.

"I spoke to the State Department during the course of this situation, I told you, at least 10 times, and I met with them," Giuliani said.