United States President Donald Trump on Saturday described his former White House staffer Omarosa Manigault Newman as a “lowlife” after she claimed in an upcoming book that he used racial slurs on the set of his reality television show, reported The Guardian. Manigault Newman was a contestant on Trump’s show The Apprentice and later served as a senior advisor to the president.

In excerpts from her book, Unhinged, which is set to release on Tuesday, Manigault Newman alleged that Trump repeatedly used the “N-word” and also used racial slurs to refer to lawyer George Conway, who is half-Filipino and is the husband of White House staffer Kellyanne Conway. Manigault Newman also wrote that she believed Trump to be “a racist, a bigot and a misogynist”.

Trump was asked on Saturday at an event in his New Jersey golf club if he felt betrayed by Manigault Newman’s allegations, reported the Associated Press. He said, “Lowlife. She’s a lowlife.”

On Friday, White House Press Secretary Sarah Sanders had criticised the allegations, calling Manigault Newman a “disgruntled former White House staffer”, according to ABC News. “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.

Last December, Manigault Newman was dismissed from the White House. On a television show later, she said, “As the only African American woman in this White House, as a senior staff and assistant to the president, I have seen things that have made me uncomfortable, that have upset me, that have affected me deeply and emotionally, that has affected my community and my people.”

Manigault Newman taped many of her private conversations during service and has quoted directly from them in the book, ABC News quoted the Washington Post as saying.

In the book, Manigault Newman also claimed that Trump exhibited signs of a “mental decline that could not be denied”, reported the Associated Press. She also described him as a man who “loved conflict, chaos and confusion; he loved seeing people argue or fight”.