An incendiary tell-all book by a reporter who helped bring down President Richard Nixon has set off a firestorm in the White House, with its descriptions of current and former aides calling President Donald Trump an “idiot” and a “liar”.

The book, Fear: Trump In The White House, by Washington Post journalist Bob Woodward is the latest to throw the Trump administration into damage-control mode with explosive anecdotes and concerns about the commander in chief.

Mr Trump decried the quotes and stories in the book on Twitter as “frauds, a con on the public,” adding that Defence Secretary Jim Mattis and chief of staff John Kelly had denied uttering quoted criticisms of the president in the book.

He also denied accounts in the book that senior aides snatched sensitive documents off his desk to keep him from making impulsive decisions.

He said in an interview with The Daily Caller, “There was nobody taking anything from me.”

The publication of Mr Woodward’s book has been anticipated for weeks, and current and former White House officials estimate that nearly all their colleagues cooperated with the famed Watergate journalist.

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”.

Mr Woodward did not immediately respond to a request for comment.

The book quotes Mr 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 denied on Tuesday.

The book says 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 coordination with Mr Trump’s campaign.

Mr Dowd, who stepped down in January, resigned after the mock interview, the book said.

“Don’t testify. It’s either that or an orange jumpsuit,” Mr Dowd is quoted telling the president.

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

Trump Woodward Book
Bob Woodward’s forthcoming book focuses on Donald Trump’s first 18 months in office (Alex Brandon/AP)

Mr 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 Three,” 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 Mattis said in a statement: “The contemptuous words about the President attributed to me in Woodward’s book were never uttered by me or in my presence.”

A Pentagon spokesman, Colonel Rob Manning, said Mr Mattis was never interviewed by Mr Woodward.

“Mr Woodward never discussed or verified the alleged quotes included in his book with Secretary Mattis or anyone within the DOD,” he said.

Mr Woodward reported that after Syria’s Bashar Assad launched a chemical weapons attack on civilians in April 2017, Mr Trump called Mr 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 ultimately ordered.

US Ambassador Nikki Haley denied on Tuesday that Mr Trump had ever planned to assassinate Mr Assad.

She told reporters at UN headquarters that she had been privy to conversations about the Syrian chemical weapons attacks, “and I have not once ever heard the president talk about assassinating Assad.”

She said people should take what is written in books about the president with “a grain of salt”.

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 Mr Trump from signing them into law, including efforts to withdraw from the North American Free Trade Agreement and from a deal with South Korea.

The book quotes Mr Trump as mocking his attorney general, Jeff Sessions, who has been a target of the president’s wrath since recusing himself from the Russia investigation.

“He couldn’t even be a one-person country lawyer down in Alabama,” Mr Trump said of Mr Sessions, according to the book.

Mr Trump did not speak to Mr Woodward until after the book’s manuscript was completed.

The Post released audio of Mr Trump expressing surprise about the book in an August conversation with Mr Woodward and dismay that he did not have an opportunity to contribute.

Mr Woodward tells Mr Trump he had contacted multiple officials to attempt to interview Mr Trump and was rebuffed.

“I never spoke to him,” Mr Trump told The Daily Caller. “Maybe I wasn’t given messages that he called. I probably would have spoken to him if he’d called, if he’d got through.”

Mr Woodward’s book was already ranked the top-selling book on Amazon on Tuesday.

Mr Trump has been increasingly critical of anonymous sources used by reporters covering his administration. Mr Woodward’s account relies on deep background conversations with sources, meaning their identities are not disclosed.

Former George W Bush press secretary Ari Fleischer defended Mr Woodward’s methodology.

“I’ve been on the receiving end of a Bob Woodward book,” he tweeted Tuesday. “There were quotes in it I didn’t like. But never once – never – did I think Woodward made it up.”