Two prominent House Democrats hit back against the Department of Justice on Thursday amid reports that the agency was opening up a criminal investigation into the special counsel's Russia investigation.

Robert Mueller's 448-page report into 2016 Russian election meddling did not charge Trump with criminal conduct but also did not exonerate the president from claims he obstructed justice.

Rep. Jerry Nadler, the chairman of the House Judiciary Committee, and Rep. Adam Schiff, the chairman of the House Intelligence Committee, issued a joint statement accusing the Justice Department of seeking "revenge" on US President Donald Trump's behalf.

"If the Department of Justice may be used as a tool of political retribution, or to help the President with a political narrative for the next election, the rule of law will suffer new and irreparable damage," the statement said.

Visit Business Insider's homepage for more stories.

Rep. Jerry Nadler, the Democratic chairman of the House Judiciary Committee, and Rep. Adam Schiff, the Democratic chairman of the House Intelligence Committee, issued a joint statement Thursday condemning the Department of Justice over reports it had opened a criminal investigation into the special counsel's Russia investigation.

The New York Times, citing two sources, reported Thursday that the Justice Department was shifting its review of the origins of the Russia investigation into a criminal inquiry. The review, said to be closely monitored by Attorney General William Barr, a Trump ally, is looking at whether the FBI's investigation into Russian election meddling and whether Trump or any of his associates had ties to it was influenced by anti-Trump sentiments.

According to The Times, the move gives John Durham, the prosecutor leading the administrative review, the power to subpoena documents and witness testimony. It also creates a bizarre scenario in which the Justice Department is investigating itself.

The Wall Street Journal also reported that the review was being changed to a criminal investigation, citing a person familiar with the matter. It was unclear what prompted the change or whether any evidence of criminal conduct was found by Durham.

Rep. Adam Schiff. J. Scott Applewhite/AP

In their joint statement Thursday, Nadler and Schiff said that if The Times' report was true, the Justice Department was operating as a "vehicle for President Trump's political revenge."

"These reports, if true, raise profound new concerns that the Department of Justice under AG Barr has lost its independence and become a vehicle for President Trump's political revenge," said the statement, which was posted on Twitter.

"If the Department of Justice may be used as a tool of political retribution, or to help the President with a political narrative for the next election, the rule of law will suffer new and irreparable damage."

Trump has repeatedly attacked the Russia investigation and has referred to it as a "witch hunt."

The special counsel Robert Mueller's 448-page report did not charge Trump with any crimes but also did not exonerate him from claims he obstructed justice.