Aboard Air Force One on Friday, President Donald Trump escalated his calls to identify the anonymous administration official who wrote the op-ed in The New York Times criticizing the President, telling reporters that the Department of Justice should investigate who wrote it.

“It’s national security,” he told reporters, according to the pool report. “I would say Jeff should be investigating who the author of that piece was because I really believe it’s national security.”

The President said he finds the ordeal unsettling, primarily because the author could have a security clearance and has access to “high level national security” meetings.

“He goes into a high level meeting concerning China or Russia or North Korea or something, I don’t want him in those meetings,” he said.

When asked whether action should be taken against the New York Times for publishing the anonymous op-ed — which was written by a “senior official” who revealed a group of administration officials are working to “thwart” President Trump’s most “misguided impulses” — Trump said he was “looking at that right now.” The President also dug his heels in on his claim that “libel laws should be toughened up,” a suggestion he also made earlier this week and a puzzling proposal given defamation laws are controlled by individual states.

“Our libel laws are pathetic,” he said. “Our libel laws should be toughened up so that if somebody writes things that are fraudulent and false, they get sued and they lose.”

As he bemoaned the “disgraceful” op-ed and labeled the new Bob Woodward book of palace intrigue a “total fraud,” Trump also bragged about his thick skin, as well as about how “highly educated” he is and his success before and after his foray into politics: “I tried politics and I started off as president, guess what happened? I won.”

“I don’t mind criticism,” he continued. “I handle it. I fight back, I guess you’ve noticed over the years.”

As one high level administration official after the other released scathing statements denying they were the wordsmith culprit, Trump appears to have bought the rebuttals.

“It doesn’t seem to be anybody very high up because everybody very high up has already said it wasn’t me,” he said. “It would be very hard if it was, if they got caught.”