The U.S. has sanctioned a North Korean company and three individuals for operating fraudulent information technology (IT) worker schemes that generate hundreds of millions of dollars for the country’s nuclear and ballistic missile programs.

In a press release on Thursday, the Treasury Department’s Office of Foreign Assets Control (OFAC) announced the designation of the Korea Sobaeksu Trading Company and three North Korean nationals — Kim Se Un, Jo Kyong Hun and Myong Chol Min — for generating revenue for Pyongyang in violation of U.N. and U.S. sanctions.