A book containing damaging allegations about the Trump administration is to be released early after lawyers tried to block publication, its author says.

Fire and Fury: Inside the Trump White House by Michael Wolff was due out on Tuesday but Mr Wolff says it will now be available for purchase on Friday.

Mr Trump's lawyers said the book contained numerous false statements.

The book cites former top aide Steve Bannon as describing a meeting with a group of Russians as "treasonous".

It also portrays Mr Trump as being surprised at winning the presidency.

The White House has disputed the book's accuracy. Mr Trump earlier said Mr Bannon - who was sacked in August - had "lost his mind" after losing his White House position.

Among a number of explosive statements, Mr Bannon reportedly said, referring to a Trump Tower meeting between top campaign officials and Russia: "They're going to crack Don Junior like an egg on national TV."

The meeting, which involved Mr Trump's eldest child Donald Trump Jr, is being investigated by Special Counsel Robert Mueller as part of his inquiry into possible collusion between Trump campaign officials and Russia to win the election.

Mr Trump strongly denies any collusion took place.

On his Breitbart radio show on Wednesday, Mr Bannon responded to the president's criticism by saying he was a "great man" and that he supported him "day in and day out".

After the president met Republican senators in the Oval Office to discuss immigration on Thursday, a reporter asked Mr Trump if his former strategist had betrayed him. He responded: "I don't know, he called me a great man last night so he obviously changed his tune pretty quick."

Mr Bannon has also been criticised by another former associate, Republican party donor Rebekah Mercer - who has also invested in Breitbart, where Mr Bannon is chairman.

"I support President Trump and the platform upon which he was elected," Ms Mercer told the Washington Post.

"My family and I have not communicated with Steve Bannon in many months and have provided no financial support to his political agenda, nor do we support his recent actions and statements."

What did Mr Trump's lawyers argue?

The legal notice, which has been published by the Washington Post, demanded that author Michael Wolff and the book's publisher "immediately cease and desist from any further publication, release or dissemination of the book".

It accused Wolff of making "numerous false and/or baseless statements" about Mr Trump and said lawyers were considering pursuing libel charges.

The attorney who wrote the letter is Charles J Harder. He also sent a cease-and-desist letter to Mr Bannon on Wednesday, saying he had violated a non-disclosure agreement.

Wolff's book makes many claims, including that:

- The Trump team was shocked and horrified by his election win
- His wife, Melania, was in tears of sadness on election night
- Mr Trump was angry that A-list stars had snubbed his inauguration
- The new president "found the White House to be vexing and even a little scary"
- His daughter, Ivanka, had a plan with her husband, Jared Kushner, that she would be "the first woman president"
- Ivanka Trump mocked her dad's "comb-over" hairstyle and "often described the mechanics behind it to friends"
- The book is reportedly based on more than 200 interviews but some of the book's excerpts have already been criticised and questioned.

Still, even if only half of what the book contains is true, it paints a damning portrait of a paranoid president and a chaotic White House, BBC North America editor Jon Sopel says.