By Agence France-Presse The White House hit back angrily Friday against accusations by an African-American former employee that President Donald Trump is a racist who repeatedly used the N-word during the making of his reality TV show. Omarosa Manigault Newman is the latest former White House employee to publish an insider memoir about her time working with Donald Trump, and it includes incendiary charges of racist language used by the president (AFP Photo/Brendan Smialowski/ MANILA BULLETIN) Omarosa Manigault Newman writes in her incendiary new book "Unhinged" that Trump was caught on mic uttering the racial slur "multiple times" during the making of his hit show "The Apprentice" prior to his presidential run, and that there are tapes to prove it. While she does not write that she herself heard Trump use the taboo language, she cites three unnamed sources, and adds that she experienced "truly appalling things" with Trump, according to The Guardian, which obtained a copy of the book ahead of its publication next week. She also claims to have personally witnessed the president use racial epithets including "Flip" and "goo-goo" to describe White House advisor Kellyanne Conway's husband, George Conway, who is half Filipino. Both terms are considered racial slurs for Filipinos. In the book, Manigault Newman makes the stunning accusation that she was offered -- and refused -- a $15,000-per-month contract from Trump's campaign to remain silent after her unceremonious dismissal last December, according to excerpts obtained by the Washington Post. The contract was for a "diversity outreach" job for the campaign, and came with a proposed non-disclosure agreement that would bar Manigault Newman from commenting about Trump or his family, the Post reported. White House spokeswoman Sarah Sanders told reporters here in New Jersey, where Trump is on vacation, that the book is "riddled with lies and false accusations." "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," Sanders said. Manigault Newman, a former Apprentice star, was once one of Trump's most high-profile supporters during his campaign. She served as director of communications for the White House office of public liaison before her dismissal last December. She writes that prior to her departure "it had finally sunk in that the person I'd thought I'd known so well for so long was actually a racist. Using the N-word was not just the way he talks but, more disturbing, it was how he thought of me and African Americans as a whole." Trump has faced allegations of racism and misogyny for years. Weeks before the 2016 election, an "Access Hollywood" tape surfaced in which Trump was heard bragging about grabbing women's genitals. The remarks caused an outcry, and some Republican lawmakers revoked their endorsement of him. At the time, an early Apprentice producer took to Twitter to say "there are far worse" behind-the-scenes tapes from the show. Manigault Newman, who is reported to have extensively taped her conversations in the White House, is expected to appear on NBC's "Meet the Press" on Sunday.