The U.S. government instructed Anthropic to prevent any foreign national from accessing the AI company’s latest and most powerful models Friday evening, according to the AI giant.
Anthropic, the company behind the popular Claude chatbot, said it had to disable access to Fable 5 and Mythos 5 for all customers — not just foreign nationals — to comply with the directive.
“The US government, citing national security authorities, has issued an export control directive to suspend all access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States, including foreign national Anthropic employees,” the company wrote in a statement posted online late Friday evening.
Anthropic’s decision to suspend user access appears to be the first time a leading AI company has taken a publicly deployed model offline due to intervention from the federal government.
“The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance,” the company wrote.
Claude’s landing page said that “Fable 5 is temporarily unavailable” as of Friday evening.
The letter issuing the directive was sent from Commerce Secretary Howard Lutnick and was written with the help of officials from the Commerce Department’s Bureau of Industry and Security, according to an administration official.
The Commerce Department did not immediately reply to a request for comment.
In its statement, Anthropic said the government had identified a specific technique that could allow users to circumvent some narrow safeguards for Fable 5. It was unclear Friday night why the Commerce Department was specifically worried about foreign nationals exploiting this weakness, or “jailbreak.”
Anthropic also said the government had only provided “verbal evidence” of the issue and said the workaround was likely also present in AI systems developed by other companies.
“We disagree that the finding of a narrow potential jailbreak should be cause for recalling a commercial model deployed to hundreds of millions of people,” the company said in its statement
Anthropic released Fable 5 and Mythos 5 on Tuesday, trumpeting the new models as the most powerful AI systems it had ever shared. The company said that these AI models are powerful enough to merit strict safety guardrails to prevent malicious or dangerous use.
“Releasing a model this capable comes with risks. Without safeguards, Fable 5’s capabilities in areas like cybersecurity could be misused to cause serious damage,” Anthropic said in its Tuesday announcement.
While both models were built on the same technical foundation, only Fable 5 was released to the general public. The Fable model includes much stronger restrictions on the types of questions that users can ask, especially on issues related to cybersecurity and biology. Mythos 5, meanwhile, was released without such safeguards to a select group of trusted partners, including key cybersecurity and infrastructure companies.
Anthropic said it believed Friday’s directive stemmed from “a misunderstanding” and hoped to reinstate access to Fable 5 and Mythos 5 as soon as possible.
Friday’s directive is the latest development in a tumultuous relationship between Anthropic and the federal government. In February, President Donald Trump and Defense Secretary Pete Hegseth moved to bar Anthropic’s products from federal agencies after the company sought stronger guardrails on how the Pentagon used its technology. At the time, Trump posted on Truth Social that “The Leftwing nut jobs at Anthropic have made a DISASTROUS MISTAKE trying to STRONG-ARM the Department of War.”
Anthropic later sued the administration, arguing that the administration’s violated Anthropic’s freedom of speech. A federal judge in California ruled in Anthropic’s favor, but the case remains active in a Washington, D.C. federal court.
Despite the dispute, Anthropic and the administration had seemed to make amends in recent weeks. Last week, the Financial Times reported that the National Security Agency was using Mythos to conduct offensive cyberattacks.
On June 2, Trump signed a landmark executive order on AI. The order directed federal agencies to bolster the government’s cyber defenses and to design a mechanism for the government to gain early access to the most powerful AI models from companies like Anthropic and OpenAI on a voluntary basis.
“We believe the government should have the ability to block unsafe deployments, as part of a statutory process that is transparent, fair, clear, and grounded in technical facts. This action does not adhere to those principles,” Anthropic wrote in its Friday statement about the directive.
