Two administrators of the Russia-based cryptocurrency exchange Garantex are facing criminal charges in the United States for allegedly helping hackers, ransomware groups, and terrorist organizations launder illicit funds.

Garantex, a Russian crypto exchange popular with ransomware gangs and darknet markets, has been taken down in an international law enforcement operation, according to a Friday announcement from the U.

The exchange, which has been linked to Russian banks under EU sanction and criminal groups, has been a target of investigators for years.