President Donald Trump denied allegations that he called Attorney General Jeff Sessions "mentally retarded" and a "dumb Southerner" behind his back.

In Washington Post journalist Bob Woodward's new book, "Fear: Trump in the White House," current and former White House aides claimed Trump had callous words for members of his cabinet.

Trump claimed he "never used those terms on anyone," but audio recordings from previous interviews reveal otherwise.

Republican lawmakers from Southern states appeared unnerved by the allegations, but stopped short of criticizing Trump directly.

President Donald Trump attempted to rebuff one of the many unflattering claims made in Washington Post journalist Bob Woodward's new book, "Fear: Trump in the White House," but previous audio recordings and news reports appear to discredit him.

In "Fear," which is sourced from a number of current and former senior White House officials, Woodward describes Trump disparaging Attorney General Jeff Sessions, according to The Post. Woodward's sources recounted Trump making pointed remarks, such as "mentally retarded" and "dumb Southerner," and claimed Trump mocked the attorney general's southern twang behind his back.

"He couldn't even be a one-person country lawyer down in Alabama," Trump said, according to Woodward's book.

Trump fired back at the allegations, and Woodward's credibility, in a late-night tweet on Tuesday.

"The already discredited Woodward book, so many lies and phony sources, has me calling Jeff Sessions 'mentally retarded' and 'a dumb southerner,'" Trump tweeted. "I said NEITHER, never used those terms on anyone, including Jeff, and being a southerner is a GREAT thing. He made this up to divide!"

Trump during an interview with Fox News. Andrew Harnik/AP

But audio recordings of previous interviews contradict Trump's claim that he never called anyone "mentally retarded." In an interview with shock jock Howard Stern from 2004, Trump claimed to recall a conversation with his golf instructor:

"I have a golf pro who's mentally retarded," Trump said, according to the Huffington Post. "I mean, he's really not a smart guy."

In another interview with Stern in 2004, Trump decried a "negative" news report that scrutinized his financial dealings and threatened to "sue their ass off."

"I was criticized in one magazine, where the writer was retarded," Trump said at the time. "He said 'Donald Trump put up $7 million ... why isn't Donald Trump putting up more money?"

In 2016, the Daily Beast also reported that Trump implied actress Marlee Matlin, a former contestant on his show "The Celebrity Apprentice," was mentally handicapped because she was deaf.

One source told The Beast that Trump, who wrote "asinine" notes during tapings of the show, once wrote: "Marlee, is she retarded??"

"[Trump] would make fun of her voice," a person who worked on the show's set said to The Beast. "Like, to make it seem like she was mentally not there? [It] sounded like he got a real kick out of it. It was really upsetting."

Trump with Attorney General Jeff Sessions on the West Lawn of the US Capitol in Washington, May 15, 2017. Reuters/Kevin Lamarque

Allegations of Trump's remarks are not new and appear to deepen the divide between him and Sessions, particularly after the attorney general recused himself from the ongoing Russia investigation in 2017. Following the recusal, Trump is believed to have lobbied Republican lawmakers to oust Sessions, who "talks like he has marbles in his mouth," according to White House aides.

Republican lawmakers appeared unnerved by the claims made from initial reviews of "Fear," but stopped short of criticizing Trump directly.

"I'm a Southerner, people can judge my intellect, my IQ, by my product and what I produce rather than what somebody else says," Sen. Johnny Isakson of Georgia said, according to The Post.

"I'm not gonna get into name calling because I don't think you should be allowed to call names — including the president," Isakson added.

Sen. Richard Shelby of Alabama ominously recounted the wide support from Southern states during the 2016 US presidential election.

"I guess the president, he says what he thinks," Shelby said in The Post. "I think the president's probably got a lot of respect for the South, I hope so. He did well there. Without the South he wouldn't be the president of the United States."