Disability advocates are none too pleased amid reports that President Donald Trump called Attorney General Jeff Sessions “mentally retarded.”

The revelation comes in a new book from renowned journalist Bob Woodward.

Set to be released Sept. 11, both CNN and The Washington Post obtained advance copies of the 448-page book titled “Fear: Trump in the White House,” which is said to be based on background interviews with dozens of people including those in the president’s inner circle.

An excerpt from the book recounts Trump mocking Sessions’ accent and saying to former-White House staff secretary Rob Porter: “This guy is mentally retarded. He’s this dumb Southerner.”

The comments are not sitting well with disability advocates.

“Words matter, and President Trump’s choice of words highlight his disregard for people with intellectual and developmental disabilities who have made it clear for decades that the term retarded is considered a slur against them,” said Marty Ford, senior executive officer for public policy at The Arc. “This incident should not go unchecked, it should be a reminder that the civil rights of people with disabilities matter, and that hateful language that degrades them should not be accepted in schools, in places of work and certainly not in the highest office of our government.”

Special Olympics’ “Spread the Word to End the Word” campaign, which urges people to pledge not to use the so-called “r-word,” told Disability Scoop, “It’s not okay for anyone to use the #Rword as an insult, no matter their office. End of story.”

The White House denied several of the claims in Woodward’s book, but did not specifically comment on reports that Trump described Sessions as “mentally retarded.”

“This book is nothing more than fabricated stories, many by former disgruntled employees, told to make the president look bad,” press secretary Sarah Sanders said in a statement issued to several news outlets.

Trump himself later took to Twitter to deny the allegation altogether.

“The already discredited Woodward book, so many lies and phony sources, has me calling Jeff Sessions ‘mentally retarded’ and ‘a dumb southerner.’ 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 wrote.

However, The Washington Post found at least two examples of Trump describing individuals as either “mentally retarded” or “retarded” during recorded interviews with Howard Stern.

(Updated: September 6, 2018 at 11:35 a.m. ET)