US President Donald Trump has described an incendiary tell-all book by a reporter who helped bring down Richard Nixon as “nasty stuff”, denying certain scenes occurred.

Fear: Trump In The White House, by veteran Washington Post journalist Bob Woodward, has angered the White House, with Trump aides quoted as calling the President an “idiot” and admitting they snatched sensitive documents off his desk to keep him from making rash actions.

It is the latest book to throw the Trump administration into damage-control mode with explosive anecdotes and concerns about the commander in chief.

On Wednesday morning (AEST), the Washington Post published details from the book, the Watergate reporter’s forthcoming examination of Mr Trump’s first 18 months in office.

Mr Trump spoke to the conservative Daily Caller after details emerged about the book, calling it “another bad book” and saying Woodward has “a lot of credibility problems”.

The President also denied that senior aides took sensitive documents from his desk, saying “there was nobody taking anything from me”.

The White House, in a statement from press secretary Sarah Huckabee Sanders, dismissed the book as “nothing more than fabricated stories, many by former disgruntled employees, told to make the President look bad”.

The Woodward book has already been refuted and discredited by General (Secretary of Defense) James Mattis and General (Chief of Staff) John Kelly. Their quotes were made up frauds, a con on the public. Likewise other stories and quotes. Woodward is a Dem operative? Notice timing?

— Donald J. Trump (@realDonaldTrump) September 4, 2018

The book quoted chief of staff John Kelly as having doubts about Mr Trump’s mental faculties, declaring during one meeting “we’re in Crazytown”.

It also says he called Mr Trump an “idiot”, an account that Mr Kelly has  denied.

“The idea I ever called the President an idiot is not true,” he said in a statement.

The book says that Mr Trump’s former lawyer in the Russia probe, John Dowd, doubted the President’s ability to avoid perjuring himself should he be interviewed in special counsel Robert Mueller’s investigation into Russian election interference and potential co-ordination with Trump’s campaign.

“Don’t testify. It’s either that or an orange jumpsuit,” Mr Dowd, who stepped down in January, is quoted as telling the President.

Mr Dowd, in a statement, said “no so-called ‘practice session’ or ‘re-enactment'” took place and denied saying that Mr Trump was likely to end up in an “orange jumpsuit”.

Secretary of Defence Jim Mattis is quoted explaining to Mr Trump why the US maintains troops on the Korean Peninsula to monitor North Korea’s missile activities.

“We’re doing this in order to prevent World War III,” Mr Mattis said, according to the book.

The book recounts that Mr Mattis told “close associates that the President acted like – and had the understanding of – ‘a fifth or sixth-grader’.”

Mr Woodward’s reporting was instrumental to the Watergate scandal. Photo: Getty

Mr Woodward reported that after Syria’s Bashar Assad launched a chemical weapons attack on civilians in April 2017, Mr Trump called Mattis and said he wanted the Syrian leader taken out, saying “kill him! Let’s go in”.

Mr Mattis assured Mr Trump he would get right on it, but then told a senior aide they would do nothing of the kind, Mr Woodward wrote.

National security advisers instead developed options for the airstrike that Mr Trump ordered.

Mr Woodward also claims that Gary Cohn, the former director of the National Economic Council, boasted of removing papers from the president’s desk to prevent Trump from signing them into law.

-AP