Mary Trump says her uncle is attempting a coup on departure from White House

'They're going to break as much as they can on the way out’

Mary Trump, the estranged niece of Donald Trump, has called the president's reaction to the election an “attempted coup”.

Ms Trump, a clinical psychologist and vocal critic of the president, has publicly spoken out over the predicament her estranged uncle faces amid diminishing re-election prospects.

“President-elect Joe Biden won legitimately and decisively. No matter how much Donald and his enablers lie and spin, nothing will change that,” she said in a tweet on Sunday night.

“But they're going to break as much as they can on the way out. Stay vigilant--this is an attempted coup.”

Mr Biden was declared winner of the 2020 presidential election by networks and news agencies on Saturday. President Donald Trump has yet to concede to the president-elect.

Following the declaration of Mr Biden’s win the Trump campaign immediately issued a statement in which the president stated the contest was "far from over".

The president has spent the majority of his time following the election announcement playing golf and making baseless claims of voter fraud in swing states that he says cost him his victory.

The campaign has filed at least seven lawsuits in battleground states since election day to challenge the ballot counts, Bloomberg reported.

Earlier this year, Ms Trump released a tell-all book on her uncle titled: Too Much and Never Enough: How My Family Created The World’s Most Dangerous Man, in which she labeled Mr Trump a “monster”.

The president’s niece reveled in Mr Biden’s and Kamala Harris’s victory on Saturday,  celebrating with a glass of champagne while wearing a Biden-Harris hat.

In an appearance on MSNBC following the president’s controversial White House press conference on Thursday before Mr Biden was declared president-elect, Ms Trump called the president “desperate”.

“Donald has never been in this place before where there’s nobody to bail him out, there’s nobody to buy him out. He’s desperate, he’s flailing, and there’s literally nothing he can do legitimately except to watch this play out helplessly,” she said.

″This wasn’t just Donald obfuscating or lying," she said. "This was Donald talking about an attempted coup. The leader of a country trying desperately to delegitimise an election. It’s obscene, and somebody’s got to step in and stop it.”

The Trump campaign has so far provided no definitive evidence of any voting irregularities.

Ms Trump filed a lawsuit against the president in September, claiming he cheated her out of tens of millions of dollars while pushing her out of the family’s real estate business.