The U.S. Treasury Department has moved to cut a Seychelles-based cryptocurrency exchange off from the American financial system for facilitating at least $16.7 billion in transactions linked to illicit activity, including North Korean money laundering.

The department’s Financial Crimes Enforcement Network (FinCEN) issued an order on Friday prohibiting U.S. financial institutions from processing transfers to or from MEXC Global, citing its dealings with North Korean financial facilitators, Russian sanctions evasion networks, Iranian actors and other cybercriminals.

FinCEN said MEXC — one of the top 20 convertible virtual currency exchanges worldwide — facilitated the receipt of approximately $350,000 by the U.S.-sanctioned