Anthropic wrote to Senators Tim Scott and Elizabeth Warren on June 10, accusing Alibaba and its AI lab of running “the largest known distillation attack” on its Claude models. Between April 22 and June 5, operators tied to Alibaba spun up about 25,000 fake accounts and ran 28.8 million prompt–response rounds, all designed to train a smaller rival model on Anthropic’s outputs. CNBC confirmed the letter and reached out to Alibaba, which has not replied. Distillation means feeding an AI’s answers back into a new model to clone its behavior. Anthropic wants Congress and the White House to push industry and cloud providers into a joint effort to spot and stop these attacks. Earlier this year, the White House Office of Science and Technology Policy issued a memo promising to help AI firms detect industrial-scale distillation, pointing back to warnings from the Trump administration. Anthropic has faced its own government roadblocks. In early June, the Commerce Department ordered the company to block all foreign nationals—including its non-U.S. staff—from using its latest Claude releases, Fable 5 and Mythos 5. Washington cited “national security authorities” but gave no details. Anthropic sent senior staffers to Washington, D.C., aiming to lift the suspension as soon as possible, though it hasn’t set a timeline.