The Justice Department on Monday declined to answer requests by House Intelligence Committee Chairman Devin Nunes, R-Calif., for more information about the reported use of FBI informants while investigating President Trump's 2016 campaign.

Nunes had given Deputy Attorney General Rod Rosenstein until 5 p.m. ET to say whether the FBI had used "informants against members or associates of the Trump campaign and if so, how many informants were used and how much money was spent on their activities?"

In his response to Nunes, Assistant Attorney General Stephen Boyd said: "Many of your requests relate to documents and information regarding issues surrounding confidential human sources that are solely in the custody and control of the FBI."

"The FBI retains and has the ability to produce the documents requested in a manner consistent with its obligation to protect confidential human sources and methods," Boyd added.

Soon after the 5 p.m. deadline passed, Adam Schiff, the Intelligence Committee's top Democrat, accused Nunes of seeking information "for the purpose of assisting the Trump legal team or, if the Department of Justice refuses, using that refusal to undermine [Special Counsel Robert] Mueller's investigation or give the President a pretext to fire Rod Rosenstein.

"For its part, in disclosing to Congress information about the pending Russia investigation, the Department of Justice is departing again from existing policy," Schiff added.

In a letter sent Sunday, Nunes accused Rosenstein of "unilaterally" limiting access to subpoenaed materials so that they could be viewed only by the so-called "Gang of Eight" -- the leaders of both parties in the House and Senate as well as leaders of the House and Senate Intelligence Committees.

In his letter, Nunes asked Rosenstein "whether the FBI and Department of Justice (DOJ) leadership intend to obey the law and fully comply with duly authorized congressional subpoenas."

In response, Boyd claimed that the department's response to the committee's document requests was "fully consistent with the law."

On Friday, the Justice Department sent Nunes' committee a classified letter disclosing whether the agency used top-secret confidential informants in the Trump campaign prior to the opening of the Russia investigation in July 2016.

In his letter, Nunes wrote that the department's letter was a "wholly insufficient response to the Committee’s requests" and asked for more information. Boyd answered that the FBI "has already responded" to Nunes' request about the use of confidential sources.

On Saturday, a spokeswoman for House Speaker Paul Ryan confirmed that the House Intelligence and Judiciary Committees had received "access to information that was sought months ago," but added that "some important requests remain to be completed."

The House Judiciary Committee and House Intelligence Committee have requested more than a million documents from the FBI and DOJ related to the Clinton investigation and surveillance of members of the Trump campaign during the 2016 presidential campaign.

Fox News' Catherine Herridge contributed to this report.