>>UPDATE: Trump wanted to assassinate Syria's Assad following chemical attack, Woodward writes

An upcoming book by journalist Bob Woodward says U.S. President Donald Trump’s chief of staff privately called him an “idiot” and presidential aides plucked sensitive documents off Trump’s desk and thought he was often unaware of foreign policy basics.

Those are some of the explosive anecdotes in Woodward’s book on Trump’s first 18 months in office. The Washington Post on Tuesday published details from “Fear: Trump in the White House.”

Woodward quotes an exasperated Chief of Staff John Kelly doubting Trump’s mental faculties, declaring during one meeting, “We’re in Crazytown.” The book shows that both Secretary of Defense Jim Mattis and Kelly privately trashed their boss as incompetent, even viewing him as a threat to national security.

Woodward also quotes Trump saying to Rudy Giuliani: "Rudy, you're a baby," Trump told the man who is now his personal attorney. "I've never seen a worse defense of me in my life. They took your diaper off right there. You're like a little baby that needed to be changed. When are you going to be a man?"

Read more:Fox News' Senior Political Analyst to Trump: Attorney General Is Not There to Protect You

And, Trump saying about Attorney General Jeff Sessions: "This guy is mentally retarded. He’s this dumb Southerner. … He couldn’t even be a one-person country lawyer down in Alabama."

Chief of Staff John Kelly on Trump: "He’s an idiot. It’s pointless to try to convince him of anything. He’s gone off the rails. We’re in Crazytown. I don’t even know why any of us are here. This is the worst job I’ve ever had."

Trump’s former lawyer in the Russia probe, John Dowd, is also said to have doubted Trump’s ability to avoid perjuring himself should he be interviewed by special counsel Robert Mueller.

The Washington Post also published the transcript and audio of a call between Woodward and Trump last month about the book in which Trump says the only way Woodward's book could be accurate is if he writes, "that nobody’s ever done a better job than I’m doing as president."

The White House didn’t immediately respond to a request for comment.

Former White House Press Secretary Ari Fleischer defended Woodward on Twitter, writing. "I've been on the receiving end of a Bob Woodward book. There were quotes in it I didn't like. But never once - never - did I think Woodward made it up. Anonymous sources have looser lips and may take liberties. But Woodward always plays is straight. Someone told it to him."