Anthropic has abruptly disabled its most advanced AI models for all users after the US government ordered it to suspend access to foreign nationals, citing national security concerns. The company said it received an export control directive to bar non-Americans from using Claude Fable 5 and Mythos 5 – models released publicly only this week after the company itself had described Fable 5 as “too powerful” to release.
“The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance,” Anthropic wrote in a statement. The order came without specific details of the national security concern, the company added. Its understanding is that the government believes it has identified a method of bypassing, or “jailbreaking”, a safeguard that would prevent Fable 5 from being used to identify software vulnerabilities.
“Anthropic disables its most advanced AI models after US order barring foreign access, citing national security concerns over jailbreak risks.”
Anthropic reviewed a demonstration of the technique and found it identified “a small number of previously known, minor vulnerabilities”. “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.
The suspension marks a dramatic reversal for Anthropic, which had just rolled out Fable 5 publicly despite warnings from technology, finance and government leaders about its potential risks. When the model was released privately in April for previewing, Anthropic said it was so intelligent it could be dangerous due to its ability to exploit or hack computer systems. The company had touted safeguards it implemented to prevent cyber hacking. Some critics questioned the warnings as inflated hype and marketing spin.
The dispute comes amid an ongoing separate lawsuit between Anthropic and the Trump administration over an order to stop government agencies using the company’s AI tools. The relationship ruptured this year after Anthropic refused to allow the US military to use its AI models for domestic surveillance and fully autonomous weapons systems. The government responded by putting Anthropic on a supply chain blacklist set to take effect later in the year.
Anthropic had as recently as Wednesday called for greater US oversight of AI, including the ability to block models with unacceptable risks. It said, however, that Friday’s government action did not follow “principles of fair and fact-based regulation”. The Pentagon’s chief information officer, Kirsten Davies, said on X that the defence department supported prioritising national security: “Some things are simply more important than revenue cycles, clickbait and pre-IPO valuation. America First. Always.”
Anthropic is expected to become a public company soon, with its private valuation nearing $1tn (£747bn). The company had earlier said the roughly 150 groups previewing Mythos would now get access to Claude Mythos 5, which has no limitations on cybersecurity or biology uses. Those groups have reported finding more than 10,000 critical security flaws in their systems. In Europe, the European Commission said it was assessing the situation, with spokesman Thomas Regnier noting it “further underlines Europe’s need for technological sovereignty”.