U.S. federal civilian agencies must remove DeepSeek products from their information technology systems, along with any third-party products or services "developed using DeepSeek implementations," under a Department of Homeland Security order. They may also no longer buy information technology products or services from the Chinese AI developer or its affiliates Homeland Security Secretary Markwayne Mullin issued the order, dated July 24, 2026, under the Federal Acquisition Supply Chain Security Act of 2018, and the department published it in the Federal Register on October 20. The notice does not define "DeepSeek implementations." The order names Hangzhou DeepSeek Artificial Intelligence Co., Ltd., the developer of the R1 and V3 models, and covers its affiliates as defined in federal…