President Donald Trump’s campaign filed an arbitration complaint against Omarosa Manigault Newman on Tuesday, alleging that the former top White House aide was in breach of a 2016 confidentiality agreement, a Trump campaign official said.

Trump’s campaign, formally named Donald J. Trump for President, took the action Tuesday against Manigault Newman with the American Arbitration Association in New York City, the official told NBC News.

The action is related to claims made by Manigault Newman in her new book, "Unhinged: An Insider's Account of the Trump White House," in which she slammed the president as racist and in mental decline.

In the days leading up its Tuesday release, Manigault Newman has also publicly shared audio recordings made in the White House of Trump and of chief of staff John Kelly.

In an arbitration proceeding, each side submits to the judgment of an independent arbitrator — typically a retired judge — who hears evidence presented by both sides and has the ability to make a ruling or penalize one side.

Attorney John Phillips, who is representing Manigault Newman, said Tuesday afternoon that "we haven't seen any legal action filed to date and don't have a comment on it."

Manigault Newman, in an interview Monday with “PBS Newshour,” admitted she had signed non-disclosure agreements for her work on the Trump campaign as well as in 2003 after her work on “The Apprentice,” but said she had never signed one for her work in the White House.

In an interview Tuesday afternoon with MSNBC's Katy Tur, Manigault Newman said, "I don't believe I violated" the campaign non-disclosure agreement.

"But I'll leave it to the lawyers," she said.

She added that she felt it was "interesting he's trying to silence me."

"What is he afraid of?" Manigault Newman said. "If he hadn't said anything derogatory about African-Americans ... then why would he go to this extent to shut me down?"

White House Press Secretary Sarah Huckabee Sanders, asked during a press briefing Tuesday about the campaign's arbitration action and whether the White House might pursue similar action, said she "wouldn't be able to comment on any ongoing legal matter."

In her book, Manigault Newman wrote that she had not signed a non-disclosure agreement for her work in the White House. She asserted in the book that within 24 hours of her departure, Lara Trump, the president's daughter-in-law, emailed her a contract to work on the president's re-election campaign for $15,000 per month, in exchange for signing a nondisclosure agreement that was "as harsh and restrictive as any I'd seen in all my years of television."

Manigault Newman wrote that she turned down the offer. She provided what she said were copies of those agreements to NBC's "Meet the Press” on Sunday.

Trump tweeted Monday that "Wacky Omarosa already has a fully signed Non-Disclosure Agreement!" It was unclear whether that remark was in reference to Manigault Newman’s non-disclosure agreement for her work on the campaign.