US President Donald Trump has one word to describe former White House staffer and fellow reality-TV star Omarosa Manigault Newman: "Lowlife".
Manigault Newman claims in an upcoming book, Unhinged, that Trump used racial slurs on the set of his reality show The Apprentice. She also says she later concluded that he is a racist and a bigot.
On Saturday, reporters asked Trump during an event at his golf club in New Jersey if he felt betrayed by Manigault Newman. He responded: "Lowlife. She's a lowlife."
Manigault Newman was a contestant on Trump's The Apprentice reality show and later served as a senior adviser to the president. In the book, she paints Trump as scattered, self-absorbed, misogynistic and insecure.
The book is set for release on Tuesday. The White House has already slammed it as "riddled with lies and false accusations".
The Associated Press purchased a copy of the book ahead of its release. In the book, Manigault Newman claims without evidence that tapes exist of Trump using the N-word repeatedly on the reality show's set.
She acknowledges she had never been able to obtain or hear the tapes but said three unnamed sources had described their contents.
She alleges that Trump has exhibited signs of a "mental decline that could not be denied" and says she went as far as printing out a study linking Diet Coke consumption to dementia and strokes and putting it in his briefing stack. She also described him as a man who "loved conflict, chaos and confusion; he loved seeing people argue or fight."
Manigault Newman also alleges that Trump allies tried to buy her silence after she left the White House, offering her $US15,000 ($A20,540) a month to serve in a "senior position" on his 2020 re-election campaign along with a stringent nondisclosure agreement. She says when she turned down the offer, she received letters from Trump's lawyers telling her to stay quiet.