President Trump says the Justice Department should launch an investigation into who in the administration wrote an anonymous op-ed questioning the President's fitness for office.

FOX's Jared Halpern has more from Washington:

The New York Times says only a senior administration official penned an anonymous opinion piece this week describing erratic behavior from President Trump. The President told reporters on Air Force One Attorney General Jeff Sessions should investigate:

(President Trump) "Jeff should be investigating who the author of that piece was, because I really believe it's national security."

President Trump has criticized the New York Times for publishing the piece and indicated he's looking into possible action against the newspaper.

In Washington, Jared Halpern, FOX News.

Follow Jared Halpern on Twitter: @JaredHalpern