WASHINGTON, D.C. — Anthropic suspended access for foreign national users to its Mythos 5 and Fable 5 artificial intelligence models following a directive from the U.S. Department of Commerce. The U.S. government cited national security concerns as the justification for this directive, which was announced by the company in a statement released Friday evening.

The U.S. government did not disclose specific details regarding the security concerns. The directive requires the company to obtain a license for the export, reexport, or domestic transfer of the specified models. The company stated it believes the government became aware of a technique to bypass Fable 5's internal security barriers. Company executives had been invited to a White House ceremony to sign the AI order, but that event was canceled before it was scheduled to occur.

The company confirmed it reviewed a demonstration of a technique used to identify minor, previously known vulnerabilities. It stated that no AI model is completely resistant to vulnerabilities. The company implemented safeguards on newer models to decrease the likelihood of misuse in cybersecurity tasks, but also reported receiving complaints from users regarding the restrictiveness of these safeguards. It collaborated with the U.S. government to conduct penetration testing on the safeguards for Fable models.

The company complied with the directive and removed model access for all users. The restriction affects many foreign nationals employed by the company who are unable to access the specified models. It initially limited the release of Mythos to a specific group of partners. While acknowledging the vulnerabilities, the company expressed disagreement with the government's action. It stated, "No estamos de acuerdo en que la detección de una posible vulneración limitada deba justificar el retiro de un modelo comercial puesto a disposición de cientos de millones de personas." Regarding the broader impact, the company said, "Si este estándar se aplicara a toda la industria, creemos que paralizaría prácticamente todos los despliegues de nuevos modelos para todos los proveedores de modelos de vanguardia."

No independent assessment was available for this report.