WATCH: President Donald Trump’s Niece Has a Message for him: ‘Resign’

In exclusive, Mary Trump said it’s “dangerous” for her uncle to lead the US.

Speaking about her influential uncle for the first time since the publication of her explosive new book, Mary Trump — President Donald Trump’s niece — on Tuesday called on the president to step down.

“If you’re in the Oval Office today, what would you say to him?” ABC News chief anchor George Stephanopoulos asked her in an exclusive interview.

“Resign,” Mary Trump responded.

She said that, after being “perverted” by the family’s deep-seated “issues,” her uncle was destined to become a man “utterly incapable of leading this country, and it’s dangerous to allow him to do so.”

“I saw firsthand what focusing on the wrong things, elevating the wrong people can do – the collateral damage that can be created by allowing somebody to live their lives without accountability,” she said. “And it is striking to see that continuing now on a much grander scale.”

Mary Trump recalled visiting with her uncle in the Oval Office three months after he was inaugurated.

“He already seemed very strained by the pressures … and I just remember thinking, ‘He seems tired. He seems like this is not what he signed up for,'” she said.

Tuesday’s exclusive interview with ABC News, to air on “World News Tonight With David Muir” and more on “Good Morning America” Wednesday, comes on the same day that Simon & Schuster is releasing her much-anticipated book, “Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man.”

The book presents a scathing depiction of the sitting president, largely drawing, Mary Trump says, from the author’s own memories, conversations with family members, and legal, financial and family documents.

Mary Trump’s uncle Robert, the president’s younger brother, unsuccessfully urged a court to block the book’s release. And another legal effort by Robert Trump to block Mary Trump from publicly promoting the new book also failed, with a New York judge ruling Monday that she was free to speak publicly.

In Tuesday’s interview, Mary Trump doubled-down on the claim in her book that Donald Trump’s father – her grandfather – was a “sociopath.”

“He was incredibly driven in a way that turned other people, including his children [and] wife, into pawns to be used to his own ends,” Mary Trump said. “It’s impossible to know who Donald might have been under different circumstances and with different parents. But clearly he learned the lesson.”

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SOURCE: ABC News – Mike Levine