Chinese cryptocurrency entrepreneur Justin Sun speaks at a financial forum in Beijing, China November 4, 2015. Picture taken November 4, 2015. REUTERS/Stringer/ File Photo

By Elizabeth Howcroft and Lawrence Delevingne

(Reuters) -Justin Sun, one of the biggest known backers of President Donald Trump's World Liberty Financial crypto venture, said on Friday his tokens connected to the project had been frozen, without giving further details.

Sun had spent at least $75 million on World Liberty Financial tokens, known as $WLFI, according to his posts on X. The tokens became publicly tradable on Monday and fell in value.

In a post on X addressed to "the World Liberty Financials team," Sun said: "during the course of operations, my tokens were unreasonably frozen" and asked the team to unlock them.

China-born crypto entrepreneur Sun did not say what the operations were, how many tokens were frozen or who had frozen them.

World Liberty said in a statement later on Friday that the company had heard "community concerns" about wallet blacklists. It did not name Sun or give any details about his tokens.

"We do not seek to blacklist anyone," the company said in its statement on X. "We respond when alerted to malicious or high-risk activity that could harm community members."

A spokesperson for Sun's crypto firm, Tron, said in a statement to Reuters that "Justin and the WLFI team are in active communication about this matter."

The public comments by Sun were a reminder of the complexities of the business ties behind the Trump family's growing fortune from crypto ventures. This year, Eric Trump - the president's second-oldest son - and others at World Liberty have spoken onstage with Sun at major crypto events in Dubai and Hong Kong. The younger Trump and Sun also frequently post on X praising each other and their respective crypto projects.

Sun is the second-largest known investor in World Liberty, and his early buy into the firm last year of $30 million matched the amount the company said it needed to jumpstart operations. Sun later said his investment totalled $75 million. Sun is also an adviser to World Liberty, and has used his crypto platforms to boost its flagship offering, stablecoin USD1.

The Trump family stake in World Liberty has made them hundreds of millions of dollars through their cut of token sales. Those riches have come at a time when Donald Trump has publicly backed the crypto industry, giving rise to broad criticisms of conflict of interest given that some of the family's business partners have in the past faced regulatory actions by the government that Trump now heads.

The U.S. Securities and Exchange Commission under the Trump administration, for example, has been exploring a resolution to its civil fraud case against Sun, Reuters reported in February.

Sun also signalled on Friday in a post on X that he planned to buy $10 million more in World Liberty tokens, and put an additional $10 million in a separate, publicly traded U.S. stock that invests in World Liberty tokens.

Blockchain data shows that the World Liberty Financial "guardian address" on Thursday blacklisted a wallet owned by Sun which holds around 545 million tokens, according to Nicolai Sondergaard, research analyst at Nansen. This means the tokens cannot be transferred out of that wallet.

Before being blacklisted, Sun transferred 50 million of the tokens to another address, the Nansen analyst said.

World Liberty had previously said early investors would be able to sell up to 20% of their token holdings.

The $WLFI tokens were trading around 18 cents on Friday, according to CoinGecko, having initially traded above 30 cents on their debut.

(Reporting by Elizabeth Howcroft in Paris and Lawrence Delevingne in Boston; Editing by Elisa Martinuzzi, Sharon Singleton, Tom Lasseter, Matthew Lewis and Tom Hogue)