House Intelligence Committee Chairman Devin Nunes, R-Calif., warned that if Obama administration officials he referred to a congressional task force for testimony on the Russia investigation refuse to cooperate, they will face subpoenas.

Nunes wrote a letter Monday to House Oversight Committee Chairman Trey Gowdy, R-S.C., and House Judiciary Committee Chairman Bob Goodlatte, R-Va., with a list of 10 names from the Obama-era State Department and White House on Monday, urging them to interview these individuals in an "open setting."

During a Monday evening interview on Fox News, Nunes emphasized that because all the people on his list are American citizens, they can be compelled to testify.

"They can plead the Fifth," he told host Laura Ingraham. "This isn't going to be like the documents where we've had to continue to fight with the Justice Department in order to have access to documents. This is much different. These are all American citizens. They will, if they do not agree to appear under oath, and testify, then they will be subpoenaed. That I could tell you for sure."

The mention of documents was a reference to Nunes', as well as other committee chairmen's, subpoenas to get the DOJ to hand over a large swath of documents related to the FBI’s investigations into both Hillary Clinton’s private email and Russia. This matter has become so contentious that last week the House passed a resolution demanding all outstanding documents, with a deadline of July 6.

Nunes has led an inquiry looking into the genesis of the federal Russia investigation as well as alleged abuse of the Foreign Intelligence Surveillance Act to spy on at least one member of the Trump campaign, all the while being panned by his Democratic colleagues. Rep. Adam Schiff, D-Calif., who is the ranking member on the House Intelligence Committee, recently called Nunes one of the "the four horsemen of this apocalypse," along with Gowdy and Reps. Mark Meadows, R-N.C., and Jim Jordan, R-Ohio, for their effort to push the DOJ to submit materials "that can be leaked or fed or misrepresented, like the infamous Nunes memorandum, in the service of the president."

The "Nunes memorandum" that Schiff referred to is the memo released by the Republicans on the House Intelligence Committee in February alleging the DOJ and FBI sought the authority to spy on Trump campaign aide Carter Page using the infamous Trump dossier, which had been funded in part by Hillary Clinton's campaign and the Democratic National Committee. While the GOP memo found that agents failed to disclose to a federal judge that ex-British spy Christopher Steele's research had Democratic benefactors, a Democratic rebuttal memo argued that the FBI did tell the judge that Steele was likely looking to "discredit" Trump.

The letter Nunes sent to Gowdy and Goodlatte on Monday is the second one in recent days. He sent one on Friday to Gowdy and Goodlatte, encouraging them to interview 17 current and former Justice Department and FBI officials. All 27 came up in the intelligence panel's search for information on potential government surveillance abuse during the 2016 election.

And more names may be on the way soon. "We will be sending a more names here later this week this week," Nunes told Ingraham.