Democrats launched their impeachment inquiry by subpoenaing Secretary of State Mike Pompeo Friday for six categories of documents elated to reported efforts by President Donald Trump and his attorney Rudy Giuliani to pressure the Ukrainian government to assist Trump’s reelection bid.

The subpoena was issued by House Foreign Affairs Committee chairman Eliot Engel (D-New York) along with House Intelligence Committee chairman Adam Schiff (D-California) and House Oversight Committee chairman Elijah Cummings (D-Maryland).

The committees had originally asked Pompeo for the documents by Sept. 16, but he did not comply. The new subpoena demands the documents by Oct. 4.

In a letter addressed to Pompeo, the three chairmen wrote, “Your continued refusal to provide the requested documents not only prevents our Committees from investigating these matters, but impairs Congress’ ability to fulfill its Constitutional responsibilities to protect our national security and the integrity of our democracy.”

The letter states that the documents “shall be part of the impeachment inquiry and shared among the Committees,” and that “Your failure or refusal to comply with the subpoena shall constitute evidence of obstruction of the House’s impeachment inquiry.”

House Speaker Nancy Pelosi (D-California) announced a formal impeachment inquiry on Tuesday. The next day, the Trump administration released a memo about Trump’s phone call with the Ukrainian president. Then on Thursday, the House Intelligence Committee released a declassified version of the whistleblower complaint about that phone call.

In addition to issuing the subpoena Friday, the three chairmen also wrote that they had scheduled depositions for five State Department officials who have been mentioned in relation to the inquiry: Deputy Assistant Secretary George Kent, Counselor T. Ulrich Brechbuhl, and Ambassadors Marie Yovanovitch, Kurt Volker, and Gordon Sondland.