Blender was designated by the Office of Foreign Assets Control after processing more than $20.5 million of illicit proceeds seized by the Lazarus Group in its March 23 heist, the Treasury said. The Lazarus Group allegedly stole approximately $620 million, the largest virtual currency heist to date.

“Today, for the first time ever, the Treasury is sanctioning a virtual currency mixer,” Treasury Undersecretary for Terrorism and Financial Intelligence Brian Nelson said in a statement. Press release. “Virtual currency mixers that facilitate illicit transactions pose a threat to United States national security interests. We are taking action against the DPRK’s illicit financial activities and will not let state-sponsored thefts and their money laundering facilitators go unaddressed.

The Treasury has been aggressive in imposing sanctions in the virtual currency space over the past year, starting with the landmark designation of Russian exchange SUEX OTC in September for facilitating payments for at least eight ransomware variants. These efforts are part of a crackdown on services used by cybercriminals to commit their misdeeds.

On Friday, the Treasury also announced the identification and blocking of four virtual currency wallet addresses used by the Lazarus Group in its alleged heist.