World Liberty Financial, the crypto venture co-founded by Donald Trump and his sons, said on Monday it had filed a defamation lawsuit in Florida state court against the Hong Kong-based crypto entrepreneur Justin Sun, as a dispute escalates between the project and one of its most prominent backers.

World Liberty posted a copy of its lawsuit on X in which it accused Sun of launching a “public smear campaign”. It alleged that Sun had improperly transferred some of his WLFI tokens that come with voting and governance rights to crypto exchange Binance and, separately, that he had placed bets that WLFI would decline in market value, known as short selling. That was part of a coordinated effort to push the token’s market price down as public trading began in September, the lawsuit alleged.