SAN FRANCISCO — Anthropic on Friday suspended access to its two most advanced AI models, Fable 5 and Mythos 5, after receiving a U.S. government export control directive citing national security concerns.
The company said it received the order from the Commerce Department late Friday afternoon, requiring it to block access for all foreign nationals. Unable to implement nationality-based restrictions in real time, Anthropic disabled the models for all users worldwide to ensure compliance.
Fable 5, a more widely available version, had been released just days earlier, while access to the more powerful Mythos 5 had been tightly controlled. The models represent Anthropic’s latest frontier AI capabilities, building on its Claude series.
“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 said in a statement.
The government directive did not provide specific details of the national security concerns, according to the company. Reports indicate officials acted over potential vulnerabilities, including a reported jailbreak method that could bypass safeguards, though Anthropic viewed the issue as manageable and already seen in competitor models.
Anthropic expressed disagreement with the approach. “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,” the company stated. “This action does not adhere to those principles.”
The move marks the latest tension between the Trump administration and leading AI developers. Earlier actions included restrictions on federal agency use of Anthropic technology and concerns over foreign access to advanced models.
Industry observers noted the decision’s broad impact, affecting even non-U.S. employees and international researchers. Some foreign officials raised concerns about implications for global AI collaboration.
As of Saturday, access to Fable 5 and Mythos 5 remained suspended. Anthropic said it is working to address the directive and restore availability where possible. Further details on the specific national security rationale or timelines for potential reinstatement were not immediately available. The company continues operations with its other AI offerings.
