'Idiot,' 'Unhinged,' A 'Sixth-Grader': Aides Fault Trump In Explosive New Book

Updated at 8:20 p.m. ET

White House staff concerned about President Trump's leadership have hidden documents from him to prevent him from signing off on certain actions, according to reports about an explosive new book from renowned Washington Post reporter Bob Woodward.

Woodward's latest book, Fear, is focused on the Trump White House and is set to be officially released on Sept. 11.

The Washington Post and CNN reported highlights from the text on Tuesday.

Woodward's book, which is described as based on in-depth interviews with those in and around the West Wing, details a dysfunctional White House in which Trump is an unpredictable boss not respected by top aides.

For example, according to the reports, former White House economic adviser Gary Cohn stole a letter off Trump's desk to keep him from formally withdrawing from the U.S. trade deal with South Korea.

Trump's current chief of staff, John Kelly, also is quoted calling Trump an "idiot" and "unhinged" and describes his White House role as the worst job he ever had.

In another reported excerpt, Woodward writes that Trump told Defense Secretary Jim Mattis that he wanted to assassinate Syrian leader Bashar Assad after a chemical attack in April 2017.

Mattis is said to have told Trump that he would get on the matter but ignored the president's request — and instead put forth very limited options for conventional airstrikes. The United States twice has attacked targets inside Syria as punishment for Assad's use of chemical weapons.

Mattis is described as among those in the administration who grew exasperated with Trump's limited intelligence; he complained that Trump has the understanding of a "fifth- or sixth-grader," according to Woodward.

White House denies the accounts

The administration seemed initially caught off guard by the reports of the book, but then it turned up the volume on its responses over the course of the day.

White House press secretary Sarah Sanders rejected the Woodward book in a statement that dismissed it as "nothing more than fabricated stories, many by former disgruntled employees, told to make the president look bad."

Continued Sanders:

"While it is not always pretty, and rare that the press actually covers it, President Trump has broken through the bureaucratic process to deliver unprecedented successes for the American people. Sometimes it is unconventional, but he always gets results. Democrats and their allies in the media understand the president's policies are working and with success like this, no one can beat him in 2020 – not even close."

The White House also released a statement attributed to Kelly in which he renewed his denial of ever calling Trump an "idiot."

Separately, Mattis denied on Tuesday that he had criticized the president in the way Woodward described.

"The contemptuous words about the president attributed to me in Woodward's book were never uttered by me or in my presence," Mattis said. "While I generally enjoy reading fiction, this is a uniquely Washington brand of literature, and his anonymous sources do not lend credibility."