(CNN) Omarosa Manigault Newman, a former White House aide and reality TV star, claims in her forthcoming book that President Donald Trump's re-election campaign offered her a lucrative contract in exchange for her signature on a strict non-disclosure agreement after her ouster from the administration last year, according to an excerpt quoted in The Washington Post.

Manigault Newman writes in "Unhinged: An Insider Account of the Trump White House" that she turned down the proposal, which would have barred her from the public criticism she has leveled at Trump since her departure. Lara Trump, a campaign adviser and the President's daughter-in-law, extended the offer to Manigault Newman shortly after White House chief of staff John Kelly fired her for "serious integrity issues," according to The Post's excerpts.

The Trump campaign declined to comment on Manigault Newman's description of the deal Lara Trump supposedly offered her.

White House press secretary Sarah Sanders on Friday dismissed the sensational claims in Manigault Newman's book, which hits shelves on August 14.

"Instead of telling the truth about all the good President Trump and his administration are doing to make America safe and prosperous, this book is riddled with lies and false accusations," Sanders said in a statement. "It's sad that a disgruntled former White House employee is trying to profit off these false attacks, and even worse that the media would now give her a platform, after not taking her seriously when she had only positive things to say about the President during her time in the administration."

Read More