House Democrats want U.S. Attorney John Durham to testify about his inquiry into the origins of the Russia investigation.

Rep. Jerry Nadler, the chairman of the Judiciary Committee, sent a letter to Attorney General William Barr on Friday requesting documents and interviews with 15 officials with knowledge of cases of personal interest to President Trump.

"The Judiciary Committee needs to examine a range of recent actions that smack of political interference, including the Department’s withdrawal of the Roger Stone sentencing recommendation; intervening in the handling of the Michael Flynn prosecution; overruling the decision to relocate Paul Manafort to Rikers Island; opening investigations into career officials involved in the Russia investigation; and a series of controversial interventions into sensitive antitrust matters," Nadler said in the four-page letter.

"Our democracy is founded on the notion that no one is above the law, and strict adherence to the rule of law has separated us from all other nations," the New York Democrat added. "Attorneys General have supported this principle on a bipartisan basis throughout our history, but that principle is now under assault. There is also a long history of Attorneys General cooperating in oversight inquiries led by both Democrats as well as Republicans, and given the stakes for our nation, we expect Attorney General Barr’s full cooperation here."

Durham, a top prosecutor in Connecticut, was on the list of officials. Nadler asked that Barr respond by March 13 "given the urgent and serious nature of these requests."

A spokesperson for Durham declined to comment and referred the Washington Examiner to the Justice Department's public affairs office. The DOJ did not immediately return a request for comment.

Trump gave Barr “full and complete authority to declassify information” in the "investigation of the investigators" last year. Durham was assigned to review possible misconduct by federal law enforcement and intelligence officials during the counterintelligence investigation into Trump's 2016 campaign by Barr, who said in the spring that "some of the facts" surrounding the inquiry "don't hang together with the official explanations of what happened." Following the DOJ watchdog’s Foreign Intelligence Surveillance Act report, Barr said he told Durham to focus just as much on the FBI’s actions after Trump’s election in November 2016 as before it.

Democrats have criticized the review as a politically motivated scheme to undermine the work of former special counsel Robert Mueller and attack Trump's perceived enemies.

“I have faith that Durham is going to get to the bottom of this,” House Intelligence Committee ranking member Devin Nunes, a California Republican, said at CPAC on Friday. “I really do.”

In October, Fox News reported that Durham expanded the investigation, broadening his team to include additional agents and resources as the period of time they were examining expanded into 2017. Weeks later, it was revealed that Durham opened a criminal inquiry in his investigation, which gave the federal prosecutor the power to impanel a grand jury and hand down indictments. Former FBI lawyer Kevin Clinesmith, who is believed to have altered a key document in FISA filings related to onetime Trump campaign adviser Carter Page, is the only person publicly known to be under criminal investigation by Durham.

Texas Rep. John Ratcliffe, a Republican member of the House's judiciary and intelligence panels, told Fox News on Sunday that he believes Durham is "specifically" looking into alleged FISA abuses, noting the Justice Department already determined that at least two of the four FISA orders targeting Page were not valid.

Durham is reportedly reviewing former CIA Director John Brennan’s analysis of Russian election interference, including scrutiny of his handling of a secret source said to be close to the Kremlin. Some of the U.S. attorney's scrutiny revolves around how the U.S. government eventually reached its January 2017 intelligence assessment on Russian election interference and whether Brennan was pushing for a biased result.

The prosecutor is also focused on at least two clashes over sensitive information, according to sources cited by the New York Times, including an internal Obama administration squabble related to restrictions placed upon yet-unknown foreign intelligence by an unnamed intelligence agency and a fight over the White House preventing the FBI from viewing U.S. emails hacked by the Russians but obtained, copied, and given to the United States by an unnamed foreign intelligence service.

Barr is set to testify before the House Judiciary Committee on March 31. He was called to testify by House Democrats, who seek answers about the Justice Department's conduct, including the scaled-back sentencing recommendation for longtime Trump associate Roger Stone and matters related to Russia and Ukraine.

Republicans have their own priorities. According to House Judiciary Committee ranking member Doug Collins, the GOP side will focus on why the Justice Department dropped its criminal investigation into former FBI Deputy Director Andrew McCabe, as well as FISA reform following a scathing DOJ watchdog report. Collins told Sunday Morning Futures that he wants to hear more about Durham's progress and whether the prosecutor has "adequate resources" for his investigation.

“The Democrats’ request today is yet another attempt to distract from the job they’ve failed to do, which is reform FISA and finally address the abuse that has plagued our nation over the last three years," the Georgia Republican said in response to Nadler's letter. "The only political interference our committee should be examining is the FBI’s unlawful surveillance of Carter Page and the Trump campaign. The fact that Democrats sent these requests just two days after canceling our FISA markup and putting our national security at risk is further proof that they care about one thing and one thing only: Attempting to take down President Trump.”