The Department of the Treasury on Friday announced first-of-their-kind sanctions against virtual currency mixer for its alleged role in a significant virtual currency heist carried out by a North Korean state-sponsored cyber hacking group.

Blender was designated by the Office of Foreign Assets Control after it processed more than $20.5 million of the illicit proceeds seized by the Lazarus Group during its March 23 heist, the Treasury stated. Lazarus Group is believed to have stolen approximately $620 million, the largest virtual currency heist to date.

“Today, for the first time ever, Treasury is sanctioning a virtual currency mixer,” said Under Secretary of the Treasury for Terrorism and Financial Intelligence Brian Nelson in a press release. “Virtual currency mixers that assist illicit transactions pose a threat to U.S. national security interests. We are taking action against illicit financial activity by the DPRK and will not allow state-sponsored thievery and its money-laundering enablers to go unanswered.”

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

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