WASHINGTON — The Justice Department unsealed charges Thursday against the alleged leader and a top associate of a Russian cybercriminal gang that U.S. and British officials say developed and distributed malware used to steal at least $100 million from banks and other financial institutions in more than 40 countries over the past decade.

Separately, the Treasury Department said that in collaboration with Britain’s National Crime Agency, it was freezing all assets of the two Russian men, along with 15 other associates and seven Russian-based organizations including Evil Corp., their alleged umbrella group.

Charged in a 10-count indictment filed in federal court in Pittsburgh were Evil Corp.’s alleged leader, Maksim V. Yakubets, 32, of Moscow, and administrator Igor Turashev, 38, from Yoshkar-Ola, Russia. The charges include conspiracy, computer hacking, wire fraud and bank fraud. The two men have not been arrested; their whereabouts are unknown. Russia and the U.S. do not have an extradition treaty.

The British agency called Evil Corp. “the world’s most harmful cyber crime group” and posted pictures on Twitter of Yakubets with his customized Lamborghini sports car and his 2017 wedding, on which it said he’d spent more than $300,000. The State Department and the FBI are offering a $5 million reward for information leading to Yakubets’ arrest and conviction, calling it the largest reward ever offered for an accused cybercriminal.

In a statement, Treasury officials also accused Yakubets of recruiting cybercriminals for Russia’s government.