A Chinese investment firm in which Hunter Biden was a part owner held a stake likely worth millions in a surveillance company that helped Beijing spy on Uyghur Muslims, the U.S. government revealed Thursday.

President Joe Biden's son long held a 10% ownership stake in Chinese investment firm Bohai Harvest, which invested in several controversial Chinese companies. One, Megvii, was sanctioned in 2019 for its alleged participation in China's repression and high-technology surveillance in Xinjiang, and again on Thursday by the Treasury Department’s Office of Foreign Assets Control.

Megvii was among eight Chinese tech firms accused of “actively support[ing] the biometric surveillance and tracking of ethnic and religious minorities in China, particularly the predominantly Muslim Uyghur minority in Xinjiang,” the Treasury Department said. The public is now prohibited from buying or selling certain securities connected to the groups, all newly labeled part of China's "military-industrial complex."