“I spend more time with the president than anyone else and we have an incredibly candid and strong relationship," Kelly said Monday in a statement issued by the White House.

"He always knows where I stand and he and I both know this story is total BS," he said. "I am committed to the president, his agenda, and our country. This is another pathetic attempt to smear people close to President Trump and distract from the administration’s many successes.”

ADVERTISEMENT According to NBC, Kelly used the insult during closed-door meetings with other White House staffers amid tense negotiations over the Deferred Action for Childhood Arrivals (DACA) program, which Trump tried to end last year. NBC cited eight current and former officials for its story.

The chief of staff, who oversaw immigration enforcement as Homeland Security secretary, believed that Trump was prepared to make too many concessions to Democrats because he did not understand the issue.

"He doesn't even understand what DACA is. He's an idiot," Kelly said in one meeting, two officials who said they were present told NBC News. "We've got to save him from himself."

A top aide to Kelly also denied the story.

"It’s complete b.s. ... He never said that,” Kelly assistant Zachary Fuentes told a group of four reporters in the West Wing. Fuentes said he was in the room for meetings that were cited in the NBC story published Monday afternoon. He later told The Hill that he has "never heard the chief of staff call the president an idiot," nor does he believe Kelly has ever done so. Kelly, "once a Marine, always a Marine, would not tolerate anyone disrespecting the commander in chief," Fuentes said. Three White House spokespeople told NBC News they do not believe Kelly called Trump an idiot, but conceded that the top aide expressed concern that the president would strike a deal that was too soft for his supporters and claimed that he was stopping Trump from making a bad deal.

The bombshell report, even with Kelly's quick denial, is likely to renew questions about Kelly’s future in the White House.

The retired Marine Corps general, who was brought on board last summer to instill order and discipline in the West Wing, has been losing clout as Trump has tired of his style.

Kelly reportedly portrays himself as one of the only administration officials keeping the president from inflicting damage upon the country, comments that will almost certainly irk Trump.

The president previously grew angry with Kelly in January when he said during a Fox News interview that Trump has “evolved” on immigration and said things during the campaign “that may or may not be fully informed.”

Trump pushed back against Kelly’s comments on Twitter, but later sought to mend any rift by telling reporters that his top adviser is “doing a great job.”

Trump publicly needled his top diplomat for weeks before firing him earlier this year.

Niall Stanage contributed.

Updated at 6:19 p.m.