The United States Department of the Treasury has announced it will impose sanctions on Czech Republic and Russia-based business Suex OTC for allegedly allowing hackers to access cryptocurrency sent as payment for ransomware attacks.

In a Sept. 21 advisory update, the Treasury Department Office of Foreign Assets Control, or OFAC, added Suex OTC to its list of Specially Designated Nationals for which “assets are blocked and U.S. persons are generally prohibited from dealing with them.” The government agency listed Suex OTC’s offices in Moscow and Prague, as well as its website and 25 crypto addresses for Ether (ETH), (XBT), and Tether (USDT).