Former President Joe Biden's aides, concerned about his physical ailments, discussed having him use a wheelchair to get around if he were reelected, according to an upcoming book said to detail the steps his administration and allies used to cover up his decline.

"Biden's physical deterioration — most apparent in his halting walk — had become so severe that there were internal discussions about putting the president in a wheelchair, but they couldn't do so until after the election," CNN's Jake Tapper and his co-author, Axios' Alex Thompson, wrote in "Original Sin: President Biden's Decline, Its Cover-Up, and His Disastrous Choice to Run Again," which will be released on May 20.

However, the aides concluded that it would not be politically tenable to have Biden, then 81, appearing on the campaign trail while sitting in a wheelchair, the authors wrote in the book, which has been published by Axios.

"Given Biden's age, [his physician Kevin O'Connor] also privately said that if he had another bad fall, a wheelchair might be necessary for what could be a difficult recovery," they wrote.

Biden, along with his family and aides, and some in the media, have been criticized for dismissing concerns about his age and mental faculties as his administration wrapped up, reports the New York Post on Tuesday.

The then-president often fell, made verbal gaffes, and showed signs of advanced age and cognitive decline, but the White House insisted that he was in good health and there was no cover-up about his issues.

Eventually, Biden pulled out of the 2024 race after issues during his presidential debate with then-candidate Donald Trump, and endorsed then-Vice President Kamala Harris to replace him on the ballot.

Biden's camp has dismissed the book's claims, with a spokesperson acknowledging that while the former president faced some physical changes as he aged, said that "evidence of aging is not evidence of mental incapacity."

The spokesperson added that "we are still waiting for someone, anyone, to point out where Joe Biden had to make a presidential decision or make a presidential address where he was unable to do his job because of mental decline. In fact, the evidence points to the opposite — he was a very effective president."

The new book also reports that the Biden team had increasing fears of a dangerous fall after Biden tripped over a sandbag at the Air Force Academy in June 2023, and started taking precautions to avoid that happening again before the November 2024 election, reports Axios.

The steps taken included figuring out how he could walk for shorter distances, insisting on handrails for the stages at his appearances, and having him wear sneakers rather than dress shoes more often. They also changed his briefings before events so he would know the steps he expected to take.

The book also reports that O'Connor had been privately expressing concerns about the toll the presidency was taking on Biden's health.

He often argued with Biden's officials to allow him to include more resting time for the president's schedule.

Biden's aides also told reporters in 2024 that the president's walk was halting because he broke his foot in November 2020 but refused to wear his prescribed walking boot.

But O'Connor said that Biden had worn the boot for 10 weeks and that the fractures were "healed as expected."

A Biden spokesman told Axios that Biden's medical exam "made clear that he had a stiffened gait caused, in part, by wear and tear to his spine — but that no special treatment was necessary and that it had not worsened."

• Axios Reporter Admits He, Mainstream Media, 'Missed' on Biden Decline
• Report: Dems Fume Over Biden's Return to Spotlight