House Intelligence Committee Chairman Devin Nunes (R-CA) is giving the Justice Department and Federal Bureau of Investigation by the end of this week to comply with subpoenas for requested information before he starts taking action.

Specifically, he is asking the DOJ and FBI to comply with a subpoena for information he requested in April, regarding the use of FBI informants who approached members of the Trump campaign in 2016. He is also asking them to fulfill any outstanding requests from his subpoena in August.

If they do not comply, next steps could include impeachment of top Justice Department officials, holding them in contempt, and passing a resolution to enforce compliance, Nunes told Fox News’ “Sunday Morning Futures.”

“I can tell you it’s not going to be pretty,” he said.

Nunes is backed by other House GOP chairmen of the Judiciary and Oversight and Government Reform Committees, as well as House Speaker Paul Ryan (R-WI).

The DOJ and FBI have resisted Nunes’ requests for months, as his committee continues to investigate how and why they began investigating the Trump campaign in the lead-up to the 2016 presidential elections.

Last month it was revealed that an FBI and CIA informant, believed to be Cambridge professor Stefan Halper, approached several members of the Trump campaign: Carter Page, Sam Clovis, and George Papadopoulos. He approached Page in June 2016, more than a month before the FBI said it had a reason to begin its investigation.

Last week former Trump campaign advisers Michael Caputo and Roger Stone informed the House Intelligence Committee that they recalled meeting a man in mid- to late-May 2016 who claimed to be a U.S. citizen of Russian descent named “Henry Greenberg” who had dirt on Clinton. Stone rejected the offer. Last month, Caputo hired an investigator, who found that the man was really a Russian national named Gennadiy Vasilievich Vostretsov who had acted as an FBI informant throughout the past 17 years.

House investigators are also curious about a Russian lawyer’s meeting with the Trump campaign at Trump Tower in June 2016, according to the Washington Examiner’s Byron York. Donald Trump Jr. was told the Russian lawyer would have dirt on Clinton. She did not have any information, and was also, unbeknownst to the campaign, at the same time working with Fusion GPS, the firm paid by the Clinton campaign and the Democratic National Committee to investigate Trump’s ties to Russia.

Last month, the New York Times reported that “at least one government informant” met with former campaign aides.

Nunes wants the DOJ and FBI to make the requested information available not just to him and the committee’s staff director, but to all members of the House Intelligence committee and investigators.

Last Thursday, Attorney General Rod Rosenstein and FBI Director Christopher Wray met with and granted access to the documents to the Gang of Eight — top leaders in the House and Senate, as well as the chairmen and ranking members of the House and Senate Intelligence Committees and their aides.

However, the meeting limited the information only to those members, and not to other members or investigators from the House Intelligence Committee, which restricts those with subject matter expertise.

“All of our members are personally invested and engaged in this issue,” an aide to Nunes said.

Potential consequences include holding Rosenstein and Wray in contempt of Congress, articles of impeachment, a resolution demanding enforcement of the subpoenas, calling Rosenstein and Wray before an open hearing, and enforcing the subpoenas in court.