House Democrat leaders this week expect to receive documents linked to their impeachment probe from some of the most powerful officials in the Trump administration, including the vice president, the Pentagon chief, and the White House chief of staff.

White House counsel Pat Cipollone, however, told the House leaders conducting the impeachment probe it will not cooperate, dismissing the process as an effort to overturn the 2016 presidential elections.

Democrat chairmen conducting the impeachment investigation have also issued subpoenas compelling Office of Management and Budget Acting Director Russell Vought (Tuesday), Ambassador to the European Union Gordon Sondland (Thursday), and U.S. Energy Secretary Rick Perry (Friday), to provide documents by their respective deadlines this week.

House Democrats have also subpoenaed documents from people outside the administration. They gave Lev Parnas and Igor Fruman, associates of Trump’s private lawyer Rudy Giuliani, an October 16 deadline to provide documents. Giuliani himself received a subpoena, demanding that he produce documents by Tuesday.

Last week, the White House made it clear in a letter to House Democrat leaders that it is not planning to cooperate with the impeachment probe. The White House has dismissed the process as an “illegitimate,” partisan,” and unfair effort to overturn the 2016 presidential election.

U.S. Secretary of Defense Mike Esper said over the weekend that he would cooperate with his subpoena. Esper, however, did not explicitly commit to honoring Tuesday’s deadline to provide documents.

“I don’t know the status of what that document preparation is, what restrictions we may have internally with regard to releasing them, the White House has a say on the release of documents as well,” he told Fox News Sunday‘s Chris Wallace.

VP Pence and Trump’s Chief of Staff Mick Mulvaney have signaled they may not meet their deadline, which falls on Tuesday and Friday, respectively. Given that the president’s executive office houses the OMB, it is unlikely that Vought will comply with his deadline on Tuesday.

After Trump blocked him from testifying, the Democrat House chairmen pursuing the impeachment probe subpoenaed Sondland.

Robert Luskin, Sondland’s lawyer, stated last Friday that his client would honor the subpoena. Sondland is scheduled to testify October 17 despite objections from the White House.

U.S. Secretary of State Mike Pompeo, Sondland’s boss, has stressed his department will fulfill its legal obligations in the impeachment inquiry.

Pompeo, however, added that the State Department would take its cues from the White House, which is refusing to cooperate.

Giuliani has not said whether he will comply with the subpoena. His associates, Parnas and Fruman, were in federal custody as of Monday afternoon on unrelated charges of campaign finance violations.

Parnas and Fruman are to remain in custody until they each secure a $1 million bond. They have refused to cooperate in the impeachment probe.

Echoing other warnings included in the subpoena letters, House Democrat chairmen pursuing the impeachment probe cautioned Pence that a failure to comply would amount to “obstruction” of justice.