WASHINGTON (Reuters) - President Donald Trump’s lawyer said on Thursday he would try to stop publication of a book that portrays an inept president in a fumbling White House and threatened legal action against former top aide Steve Bannon over “defamatory” comments in the book.

“Fire and Fury: Inside the Trump White House” by author Michael Wolff set off a political firestorm with its portrayal of Trump as not particularly wanting to win the U.S. presidency in 2016 and unprepared for the job.

Some of the harshest commentary came from Bannon, the right-wing firebrand who headed the final stage of Trump’s campaign and became chief strategist at the White House before being fired in August.

Charles Harder, Trump’s personal lawyer, in a legal notice provided to Reuters, warned of possible claims including libel against Wolff and publisher Henry Holt & Co and threatened to try to block publication of the book. Harder also told Reuters that “legal action is imminent” against Bannon.

Henry Holt said in a statement it had received a cease-and-desist letter from Trump’s attorney but would go ahead with publishing the book.

Earlier, the publishing house said that “due to unprecedented demand,” it would release the book on Friday morning, rushing it to print after previously planning to put it out next Tuesday.

Wolff did not respond to a request for comment.

Trump tweeted on Thursday night: “I authorized Zero access to White House (actually turned him down many times) for author of phony book! I never spoke to him for book. Full of lies, misrepresentations and sources that don’t exist. Look at this guy’s past and watch what happens to him and Sloppy Steve!”

Trump cut ties with Bannon on Wednesday, saying his former adviser had “lost his mind,” in a blistering statement issued after comments attributed to Bannon in the book were made public.

White House spokeswoman Sarah Sanders heaped scorn on Bannon and the book at her briefing on Thursday. She said Breitbart News should consider firing Bannon and attempted to cast doubt on Wolff’s accuracy.

She called the book “some trash” that came from “an author that no one had ever heard of until today.”

“This book is mistake after mistake after mistake,” she said.

Trump lawyers sent a cease-and-desist letter to Bannon on Wednesday asking him not to disclose any confidential information. They said Bannon had breached an agreement by communicating with Wolff about Trump, his family and the campaign and made “disparaging statements and in some cases outright defamatory statements” about them.

Author Michael Wolff on the set of NBC's 'Today' show prior to an interview about his book "Fire and Fury: Inside the Trump White House". REUTERS/Brendan McDermid

In the book, Bannon was quoted as describing a June 2016 meeting with a group of Russians at Trump Tower in New York as “treasonous” and “unpatriotic.” The meeting, held after the Russians promised damaging information on Democratic presidential candidate Hillary Clinton, was attended by Donald Trump Jr., Trump’s son-in-law, Jared Kushner, and Paul Manafort, Trump’s campaign manager at the time.

Trump’s statement also diminished Bannon’s role in the election victory and accused him of leaking to the media. Before joining the campaign, Bannon headed the conservative Breitbart News website and proved to be a divisive figure in the White House. He returned to Breitbart after being fired, although he is reported to have continued to talk with Trump.

‘CHANGED HIS TUNE’

Bannon’s reaction to the book controversy has been muted. In interviews with Breitbart News after the news broke, he called Trump a “great man” and pledged continued support for the president’s agenda.

The president took note. “He called me a great man last night so he obviously changed his tune pretty quick,” Trump told reporters on Thursday. “I don’t talk to him. That’s a misnomer.”

Bradley Moss, a Washington lawyer specializing in national security law, said any non-disclosure agreement would not apply to Bannon once he became a government employee. The government has far less power to limit speech by employees than private companies, Moss said.

A lawsuit could hurt Trump because Bannon’s lawyers would be entitled to interview White House officials and collect potentially damaging documents from them in his defense, Moss said.

“I assume the cease-and-desist letter is aimed primarily at the public,” added Michael Dorf, a professor at Cornell Law School. “The idea that he could block publication is absurd.”

On Thursday, the White House also said no personal devices, including cellphones, would be allowed in the White House West Wing beginning next week for security purposes. The moves followed the Bannon split but had been considered for some time, White House officials said.

Bannon helped Trump shape a populist, anti-establishment message and had been the president’s link to his hard-line conservative base of support, which is often at odds with the Republican Party establishment.

The story that triggered the Trump-Bannon split was an offshoot of the investigation into whether Trump campaign aides colluded with Russia to sway the election to Trump, allegations Trump and Moscow deny.

Manafort and business associate Rick Gates, another campaign aide, pleaded not guilty in November to federal charges brought by Special Counsel Robert Mueller including conspiracy to launder money. Manafort sued Mueller on Wednesday, alleging that his investigation exceeded its legal authority.