A probe by Attorney General William Barr into the origins of the Russia investigation has changed from an administrative review into a criminal investigation, a person familiar with the review confirmed to NBC News.

The review is being conducted by Connecticut U.S. Attorney John Durham. The New York Times first reported Thursday that the administrative review has turned into a criminal investigation.

It’s not clear when the change occurred, but the probe began in May as an administrative review.

The US justice department has launched a criminal investigation into the origins of the Mueller inquiry, US media report.

An administrative review into the special counsel's investigation of 2016 election interference began in May.

But the switch to a criminal probe means investigators can now issue subpoenas for testimony and documents.

President Trump has long alleged Robert Mueller's probe of reports of collusion with Russia was a "witch hunt".

U.S. Attorney John Durham opened a criminal inquiry in his investigation into the origins of the Trump-Russia investigation and into the conduct of the Justice Department, FBI, and Intelligence Community during their scrutiny of possible connections between the Trump campaign and the Kremlin.

The significant new move in the DOJ’s investigation of the investigators, which would give Durham the power to impanel a grand jury and hand down indictments, according to the New York Times.

The DOJ did not immediately return the Washington Examiner’s request for comment.