President Donald Trump said Friday he wanted Attorney General Jeff Sessions to launch an investigation into who authored the explosive anonymous opinion article published in The New York Times earlier this week.

“Jeff should be investigating who the author of that piece was, because I really believe it’s national security,” Trump told reporters aboard Air Force One.

The op-ed writer, identified only as a senior administration official, said some members of the administration are trying to thwart Trump as part of a "resistance."

Referring to the author of the piece, Trump said he wanted the Justice Department to "take a look at what he had, what he gave, what he's talking about — also where he is right now."

"I don't want him in those meetings," Trump added, referring to "high level" meetings "concerning China or Russia or North Korea" that would have required a security clearance.

Asked if he was considering taking action against The Times, Trump replied, "We're going to see."

"I’m looking into that right now," he added.

It's not clear what national security reasons would prompt a Department of Justice investigation. It is not a crime to leak information that is not classified.

Asked for clarification whether the president was directing Sessions to investigate The New York Times op-ed or opining that Sessions should, White House Press Secretary Sarah Sanders said, "opining."

“Look, he's concerned that someone is trying to undermine the executive branch and he wants it looked at," she said.

Sanders was also asked what law the White House alleges was broken by the op-ed author. She said she couldn't identify one, and pointed out that she's not a lawyer.

Asked for a response to Trump's call, a Justice spokesperson told NBC News, "the Department does not confirm or deny investigations."

The Times, in an statement, said it would not reveal the writer's identity.

"We're confident that the Department of Justice understands that the First Amendment protects all American citizens and that it would not participate in such a blatant abuse of government power," the company said. "The President's threats both underscore why we must safeguard the identity of the writer of this Op-Ed and serve as a reminder of the importance of a free and independent press to American democracy."

In the two days since The Times published the piece, Trump has relentlessly lashed out at the anonymous author, as well as the newspaper for publishing the piece.

And on Thursday, more than two dozen cabinet, cabinet-level and other top officials in the Trump administration rushed to deny they were behind the article.

Trump said if he discovered that any of those people — who had issued denials — actually wrote the piece, they’d be "shunned" for life.

"A lot of the people have said I didn’t do it, they wrote very strong statements," he said. "When you say that, if it were you, you'd be shunned for the rest of your life."

"Eventually the name of this sick person will come out," he added.

Trump also wouldn’t rule out the possibility of asking people to take a polygraph test to help weed out the author.

"People have suggested it," he said.

In the piece, the author asserted that a handful of appointees, serving at the highest levels of the Trump administration, consider the president to be "amoral," and are working against Trump from within "to frustrate parts of his agenda and his worst inclinations.

The administration official also confirmed reports that there were once internal Cabinet discussions about removing Trump from office by invoking the 25th Amendment, but said in The Times that now "we will do what we can to steer the administration in the right direction until — one way or another — it's over."

Meanwhile, in the wide-ranging back-and-forth with reporters Friday, Trump also said he would be willing to meet with special counsel Robert Mueller’s team “under certain circumstances.”

But, he added, “I don’t want to be set up with a perjury trap.”

In addition, Trump was asked about the allegation in Bob Woodward’s new book "Fear: Trump in the White House" that Gary Cohn, his one-time top economic adviser, snatched a document off his desk that the president was going to sign that would have withdrawn the U.S. from a trade pact with South Korea.

"He never took a memo off my desk," Trump said Friday. "Gary Cohn, if he ever took a memo off my desk, I would have fired him in two seconds. He would have been fired so fast."

"He would have been fired within the first second that it took place," Trump added.