WASHINGTON (Reuters) - U.S. President Donald Trump said he is unsure whether Defense Secretary James Mattis is planning to step down from his post, but told CBS’ “60 Minutes” in a pre-taped interview that the retired general might and that he regards Mattis as “sort of a Democrat.”

“It could be that he is” planning to depart, Trump said, according to an excerpt of a transcript released on Sunday before the show airs. “I think he’s sort of a Democrat, if you want to know the truth. But General Mattis is a good guy. We get along very well. He may leave. I mean, at some point, everybody leaves. Everybody. People leave. That’s Washington.”

This marks the first time that the Republican president has publicly said anything negative about Mattis, who last month told reporters not to take seriously reports that he may be leaving.

Asked about Trump’s remarks, Pentagon spokesman Colonel Rob Manning said in a brief statement: “Secretary Mattis is laser-focused on doing his job — ensuring the U.S. military remains the most lethal force on the planet.”

Mattis’ future has become a focus of media speculation, particularly after last month’s release of a book by Watergate reporter Bob Woodward that portrayed Mattis privately disparaging Trump to associates.

Mattis has strongly denied making any such remarks.

Trump had been deferential toward Mattis, saying on Sept. 5 his defense chief would remain in his job.

Mattis is not political by nature, and previously made no secret of the fact that he was not looking to become secretary of defense - or even return to Washington - when Trump was elected.

The retired Marine general had stepped down from the military in 2013 and taken a job at Stanford University. He told his Senate confirmation hearing last year he was “enjoying a full life west of the Rockies” when the call came about the position.

Asked last month about reports he may be leaving, Mattis said: “I wouldn’t take it seriously at all.”

Western officials privately extol Mattis, whose standing among NATO allies has risen as they become increasingly bewildered by Trump’s policies on trade and Iran and disoriented by his outreach to Russian President Vladimir Putin.

One factor thought to have darkened Mattis’ prospects is this year’s arrival in the White House of Mira Ricardel, who now has the powerful post of deputy national security adviser and is believed to dislike Mattis, current and former officials have told Reuters.

He is also seen as less hawkish on Iran than Secretary of State Mike Pompeo and White House National Security Adviser John Bolton.

Mattis has a dim view of journalism about inside-the-beltway politics in Washington, using the word “fiction” to describe Woodward’s book and similar reporting about closed-door conversations among U.S. national security leaders.

Asked about the reports speculating about his departure, Mattis said on Sept. 18: “It’s like most of those kinds of things in this town.

“Somebody cooks up a headline. They then call to a normally chatty class of people. They find a couple of other things to put in. They add the rumors... Next thing you know, you’ve got a story,” he said.