Trump defends his mental capacity, calls himself 'genius'

Washington :  US President Donald Trump, in an extraordinary defence of his mental capacity and fitness for office, described himself on Saturday as a "genius", after a new book suggested that top White House aides feared he was unfit for the job.

In a series of Twitter messages that seemed to respond to revelations in author Michael Wolff's new book "Fire and Fury", Trump defended himself by charting his rise to the presidency, saying one of his chief assets throughout his life was "being, like, really smart".

Trump cited his career in business and reality television and his victory in last year's election as evidence of his mental prowess. 

He again lashed out at the ongoing special counsel investigation into his campaign's contacts with Russian operatives, calling suggestions that he colluded with Moscow a "total hoax on the American public".

The book included depictions by top White House staff members painting Trump as an "uninformed and at times erratic President", the Washington Post reported.

Late Friday, Trump blasted Wolff as a "total loser", and the President mocked his former campaign chairman and White House adviser, Stephen K. Bannon, who was a key source for the book. 

Bannon criticized other aides and Trump's son, calling a meeting at Trump Tower last year between Donald Jr and a Russian lawyer "treasonous".

White House aides have mounted an all-out attack on the book, calling it "fiction" and a "complete fantasy". And Trump's lawyers sent cease-and-desist letters to Wolff and his publisher demanding that they do not release the book. 

But the publisher, Henry Holt, moved up the release date from later this month to Friday amid the publicity and hard copies were quickly sold out in the Washington area.

"It's disgraceful and laughable," White House Press Secretary Sarah Huckabee Sanders said while responding to suggestions that Trump was "mentally unfit for office".

"If he was unfit, he probably wouldn't be sitting there and wouldn't have defeated the most qualified group of candidates the Republican Party has ever seen. This is an incredibly strong and good leader. 

"That's why we've had such a successful 2017 and why we're going to continue to do great things as we move forward in this administration," she said.