House Democrats subpoena Pompeo for documents related to Giuliani's Ukraine efforts It's the first subpoena issued since the impeachment pursuit.

House Democrats issued subpoenas for Secretary of State Mike Pompeo and five other State Department officials on Friday as they ramp up their investigation into President Donald Trump and his personal lawyer Rudy Giuliani's effort to pressure Ukraine's new president to investigate Trump's political opponents.

The subpoenas are for documents related to the State Department's role in facilitating Giuliani, including communications with him and records around Trump's phone call with Ukrainian President Volodymyr Zelenskiy in July. That call and the White House's decision to withhold $400 million of U.S. military assistance to Ukraine are at the heart of a whistleblower complaint that has roiled Washington and sparked House Democrats to begin impeachment proceedings.

Rep. Eliot L. Engel, chairman of the Foreign Affairs Committee, Rep. Adam Schiff, chairman of the Intelligence Committee, and Rep. Elijah E. Cummings, chairman of the Oversight Committee, made the announcement in a joint statement, nearly three weeks after first asking Pompeo for the documents. On Monday, the three chairs said they would give Pompeo until Thursday to inform them on how he will comply, or else he would face subpoenas.

"Your failure or refusal to comply with the subpoena shall constitute evidence of obstruction of the House’s impeachment inquiry," the chairmen wrote. They require documents to be produced in one week, by Oct. 4.

The State Department has previously declined to comment on the requests for documents.

But Pompeo defended the department's actions Thursday, telling 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," he said, which is "to tighten our relationship [and] to help end corruption in Ukraine."

The committees also notified Pompeo that they'd scheduled depositions in the coming weeks for five senior State Department officials, all of whom have become embroiled in the investigation.

Giuliani has spent months now trying to pressure Zelenskiy's government to investigate unfounded allegations of corruption by former Vice President Joe Biden and his son, Hunter, and of election interference against Trump's 2016 presidential campaign by Ukrainian officials, accused of leaking details about then-campaign manager Paul Manafort and his work for the corrupt Russian-backed oligarch who once led Ukraine.

In particular, House Democrats alleged that Trump withheld $400 million of military aid from the Pentagon and State Department, including light arms, maritime security equipment and special ops gear, a week before the call to pressure Zelenskiy.

Two ambassadors, U.S. special envoy for Ukraine Ambassador Kurt Volker and U.S. Ambassador to the European Union Gordon Sondland, facilitated Giuliani's efforts to get in touch with Zelenskiy and were briefed on his meetings with Zelenskiy's officials, according to the former New York City mayor.

The State Department has confirmed that Volker put Giuliani in touch with Zelenskiy adviser Andriy Yermak at Yermak's request. In an interview with Fox News Tuesday, Giuliani described it as the department directing him to act -- a comment Pompeo declined to respond to on Thursday.

The department's counselor Ulrich Brechbuhl -- a top Pompeo adviser, former West Point classmate, and longtime friend -- was on the July 25 call, according to the whistleblower's complaint, although a U.S. official denied that he was. Brechbuhl is among the five officials scheduled for a deposition.

The fourth official is Deputy Assistant Secretary of State for European and Eurasian Affairs George Kent, who oversees policy for Ukraine.

The fifth official is the U.S. envoy who was discussed by Trump and Zelenskiy in their call, former U.S. ambassador to Ukraine Marie Yovanovitch. A career diplomat still in the Foreign Service and serving as a fellow at Georgetown University, Yovanovitch reportedly ended her term in Kyiv months early when she departed in May. Giuliani claimed in an interview that she was "fired" after he and Ukraine's former public prosecutor trashed her for obstructing investigations into corruption.

That's an allegation the State Department has fiercely denied. In March, a spokesperson called it an "outright fabrication" to The Hill newspaper and said it "does not correspond to reality" to Radio Free Europe/Radio Liberty, adding to RFE/RL that "such attacks redouble our resolve to help Ukraine with the struggle against corruption."

Trump, however, appears to believe them. In his call with Zelenskiy in July, he called Yovanovitch "bad news," with Zelenskiy thanking Trump for being "the first one who told me that she was a bad ambassador."

The State Department did not respond to requests for comment on whether Yovanovitch was recalled by the White House and whether they stood by their previous defense of her.