Donald Trump meets the definition of a fascist and “prefers the dictator approach to government”, his former White House chief of staff has told The New York Times.

With less than two weeks until the November 5 US election, John Kelly, a long-time Trump critic, told the NYT that the former US president had no understanding of the Constitution or the concept of the rule of law.

Kelly said the former president would seek to rule like an authoritarian if he returned to the White House.

In the interviews published on Tuesday (US time), he quoted Trump as having told him German Nazi dictator Adolf Hitler “did some good things”.

Trump’s team has denied the accounts.

“He certainly prefers the dictator approach to government,” Kelly said, according to the newspaper.

“Certainly the former president is in the far-right area. He’s certainly an authoritarian, admires people who are dictators – he has said that. So he certainly falls into the general definition of fascist, for sure.”

Trump, for his part, fired off a tirade against Kelly on his Truth Social platform.

“Even though I shouldn’t be wasting my time with him, I always feel it’s necessary to hit back in pursuit of THE TRUTH. John Kelly is a LOWLIFE, and a bad General, whose advice in the White House I no longer sought, and told him to MOVE ON!” he wrote.

A retired US Marine Corps general, Kelly was Trump’s White House chief of staff from 2017 to 2019.

His relationship with Trump has since soured, and both men are open about their disdain for each other.

Kelly is the latest in a string of former Trump staffers to come out against the Republican candidate.

Former chair of the Joint Chiefs of Staff, Mark Milley told Watergate journalist Bob Woodward that Trump was a “fascist to the core”, while multiple former press aides are actively campaigning against Trump, saying he is unfit to serve as president.

Kelly also told The Atlantic that Trump had said he wished his military personnel showed him the same deference Hitler’s Nazi generals showed during World War II.

Trump campaign spokesman Steven Cheung hit back at Kelly, saying he had “totally beclowned himself with these debunked stories”.

But Trump’s election rival, Vice President Kamala Harris, said on Wednesday that the reported remarks were troubling.

“It is deeply troubling and incredibly dangerous that Donald Trump would invoke Adolf Hitler, the man who is responsible for the deaths of six million Jews and hundreds of thousands of Americans,” she said outside her official residence.

“In a second term, people like John Kelly would not be there to be the guard rails against his [Trump’s] propensities and his actions.”

Kelly has previously been critical of Trump. He is not privy to internal discussions inside the former president’s orbit and so cannot speak with certainty about how Trump will govern.

But Harris has seized on comments from Trump during a Fox News event in December, when he said that if he won the 2024 election he would be a dictator, but only on “day one” – to close the US’s southern border with Mexico and expand oil drilling.

Harris and fellow Democrats argue that Trump is a threat to US democracy, something Trump denies and has said is true of the Democratic candidate.

Retired US Army brigadier general, Republican Steve Anderson, said on a media call organised by the Harris campaign that he was disappointed Kelly did not go as far as endorsing Harris after his latest criticism.

Kelly told the Times that, as a former military officer, he was not endorsing any candidate.

-with AAP