If Mary Trump were in the Oval Office with her uncle Donald Trump today, she would tell him to resign, she told ABC's George Stephanopoulos in an interview to support her explosive tell-all book about the President.

Mary Trump spoke about visiting her uncle in the White House in 2017 a few months after the inauguration and said he "already seemed very strained by the pressures."

"I just remember thinking, 'He seems tired. He seems like this is not what he signed up for,'" she told Stephanopoulos in an interview clip that aired Tuesday.

Asked what she would say if she were to visit him in the Oval Office today, Mary Trump replied, "resign."

Her message follows the release of her book, "Too Much and Never Enough: How My Family Created the World's Most Dangerous Man." In the book, she gives scathing criticism of the President, in which she accuses him of being a "sociopath" and charges that his "hubris and willful ignorance" dating back to his early days threatens the country.

Her tell-all book is the second in as many months to present a withering portrait of the President -- and like former national security adviser John Bolton, her book sparked an unsuccessful legal campaign to stop its publication. On Monday, the New York State Supreme Court lifted a temporary restraining order allowing Mary Trump to promote her book.

She writes that some of the book is based on her own memory, and in parts she reconstructed some dialogue based on what she was told by some members of the family and others, as well as legal documents, bank statements, tax returns and other documents.

In her interview with Stephanopoulos, Mary Trump also stood by a claim in her book that her uncle paid someone to take SAT tests for him to help him get into the University of Pennsylvania, which the White House has denied, though she acknowledged that she can't prove the identity of the person.

She also accused Donald Trump's father of creating a toxic family dynamic that explains the President's behavior, telling Stephanopoulos she sees "parallels" between how the family operated and how the country is operating.

"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. "If I can do anything to change the narrative and to tell the truth, I need to do it. Because I don't believe the American people had the entire truth four years ago."

The President has not immediately commented on his niece's interview with ABC, though last week, White House press secretary Kayleigh McEnany called the tell-all a "book of falsehoods."

One member of the President's immediate family, however, appeared to reference Mary Trump in a tweet Wednesday morning.

"Every family has one ...," tweeted Eric Trump, the President's son, nodding to a familiar expression about black sheep. (Text, excluding headline, courtesy CNN)

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