NEW YORK (AP) — A lawyer for Sam Bankman-Fried signaled Thursday that the onetime cryptocurrency darling is challenging the validity of new charges added to an indictment after he agreed to be brought to the United States in December from the Bahamas rather than fight extradition.

Attorney Mark Cohen told a Manhattan federal court judge that his 31-year-old client, a founder of the cryptocurrency exchange FTX, was pleading not guilty to new charges lodged against him in recent weeks in what a prosecutor has labeled as one of the biggest frauds in American history.

But Cohen quickly added that although he was pleading not guilty to the new charges, Bankman-Fried was not acknowledging that he can be tried on them. He didn't elaborate and left the courthouse quickly just before his client was ushered to a waiting vehicle.

Earlier this week, a rewritten indictment charged Bankman-Fried with a new conspiracy count, alleging that he violated the anti-bribery provisions of the Foreign Corrupt Practices Act by directing the payment of $40 million in bribes to a Chinese official or officials to free up $1 billion in cryptocurrency that was frozen in early 2021.

FTX filed for bankruptcy on Nov. 11, when the global exchange ran out of money after the equivalent of a bank run. He has remained free on a $250 million personal recognizance bond that requires him to stay with his parents in Palo Alto, California. His trial is tentatively set to begin in the fall.

Bankman-Fried previously pleaded not guilty to charges alleging that he cheated investors out of billions of dollars before his business collapsed.

In late February, a rewritten indictment brought new fraud charges against him and raised the maximum prison time he could face if convicted from 115 years to 155 years.

His not guilty plea entered through Cohen on Thursday also applied to those new charges.