US President Donald Trump has rejected an author's accusations that he is mentally unfit for office,and says his track record shows he is "a very stable genius".
- Wolff told BBC Radio that he believed Trump is unfit for office
- He said White House staff described Trump as a child needing "immediate gratification"
- Trump is to undergo physical examination on January 12, the first of his presidency
Michael Wolff, who was granted unusually wide access to the White House during much of the President's first year, has said in promoting his new book that Mr Trump is unfit for the presidency.
Mr Trump, in a series of morning tweets, said his Democratic critics and the US news media were bringing up the "old Ronald Reagan playbook and screaming mental stability and intelligence" since they had not been able to bring him down in other ways.
Reagan, a Republican who was the US president from 1981-1989, was diagnosed with Alzheimer's disease in 1994 and died in 2004.
"Actually, throughout my life, my two greatest assets have been mental stability and being, like, really smart," Mr Trump said on Twitter.
"I went from VERY successful businessman, to top T.V. Star … to President of the United States (on my first try).
"I think that would qualify as not smart, but genius….and a very stable genius at that!"
Mr Trump made the comments from the presidential retreat at Camp David, Maryland, where he was meeting Republican congressional leaders about their legislative agenda for the year.
Wolff's book Fire and Fury: Inside the Trump White House has proved to be another shock to the system for Mr Trump and his top aides, coming just as he starts his second year in office.
The book, dismissed by Mr Trump as full of lies, depicts a chaotic White House, a President who was ill-prepared to win the office in 2016, and Trump aides who scorned his abilities.
Wolff told BBC Radio in an interview broadcast on Saturday that he believed Mr Trump is unfit for office.
He said on NBC News on Friday that White House staff around Mr Trump treated him like a child.
"The one description that everyone gave, everyone has in common — they all say he is like a child," Wolff said.
"And what they mean by that, he has a need for immediate gratification. It's all about him."
"This man does not read, does not listen. He's like a pinball, just shooting off the sides."
Trump is to undergo physical examination on January 12, the first of his presidency.