The Trump family's World Liberty Financial crypto venture is being sued by one of its billionaire backers over allegations of extortion.

Justin Sun has accused World Liberty of an "illegal scheme" to seize his WLFI tokens, a cryptocurrency issued by the company.

Sun alleges the firm, co-founded by US President Donald Trump and his son Eric Trump, has "frozen" all of his tokens and stripped him of his right to vote on governance issues.

World Liberty has denied wrongdoing and accused Sun of "playing the victim while making baseless allegations to cover up his own misconduct".