Trump family is ready for a battle against his niece Mary over her upcoming tell-all book
Donald Trump, left, with father Fred Trump (Screen cap).

In an Oval Office interview last week, President Donald Trump told Axios that his brother's daughter isn't allowed to write a tell-all book about the Trump family because she signed a non-disclosure agreement.

Trump's late brother, Fred Trump Jr. died many years ago, but his daughter Mary Trump announced that she would write a book about her experience fighting for her father's inheritance after her grandfather died. According to Ms. Trump, the president and his sister were horrific in the battle to obtain what was left of the late Fred Trump's money.

"She's not allowed to write a book," Trump told Axios at the White House. "You know, when we settled with her and her brother, who I do have a good relationship with — she's got a brother, Fred, who I do have a good relationship with, but when we settled, she has a total ... signed a nondisclosure."

Trump explained that the NDA was a "very powerful one. ... It covers everything."

Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man is scheduled to be published on July 28.

Trump said that his brother Robert was "very angry" about the news about the family's in-fighting.

"I have a good relationship with [Mary Trump's] brother," said Trump. "I actually had him — he was in here. He was sitting right in the seat where you are last week, unrelated to that. I didn't even know — maybe two weeks ago. I didn't even know about a book coming out until just the other day."

Trump also revealed he didn't know that Mary Trump alleged the president "dismissed and derided" his father when he began to decline from Alzheimer's Disease.

"It's totally false; the opposite," claimed Trump. "Actually, the opposite. I always had a great relationship. I didn't know that she said that. That's a disgraceful thing to say."

Read the full report from Axios.