The criminal charges against Semenov and Storm, which include conspiracy to commit money laundering and sanctions violations, come one year after the U.S. Treasury banned Tornado Cash on allegations that it supports North Korea.

Waymaker Law, the firm representing Semenov, did not immediately respond to a request for comment. Neither did the FBI.

Storm, a naturalized US citizen and resident of Washington state, was arrested on Wednesday in conjunction with the charges.

A lawyer for Storm, Brian Klein, said in a statement: "We are incredibly disappointed that the prosecutors chose to charge Mr. Storm because he helped developed software, and they did so based on a novel legal theory with dangerous implications for all software developers. Mr. Storm has been cooperating with the prosecutors' investigation since last year and disputes that he engaged in any criminal conduct."

Semenov, a Russian citizen, was sanctioned on Wednesday by the Treasury Department. He is not in U.S. law enforcement custody, according to a statement by the U.S. Attorney for the Southern District of New York.

(Reporting by David Ljunggren; Editing by David Gregorio)

By Christopher Bing and Zeba Siddiqui