Artificial intelligence company Anthropic said Friday it has temporarily taken its newest AI models, Fable 5 and Mythos 5, offline after receiving a directive from the Trump administration aimed at preventing access by foreign nationals.

The move marks the most significant effort so far by the US government to limit access to cutting-edge AI technology. Anthropic had only recently launched Fable 5, a scaled-down version of its more advanced Mythos 5 model. Access to Mythos 5 had already been tightly restricted because of cybersecurity concerns.

In a statement, Anthropic said it disagreed with how the government handled the matter, noting that it received the directive on Friday afternoon without any explanation of the specific national security risks involved.

The company said the government should be able to block potentially unsafe AI deployments through a process that is transparent, fair and based on technical evidence. It added that the current action did not meet those standards.

Anthropic described the situation as a "misunderstanding" and expressed hope that access to the models would be restored soon.

The US Commerce Department did not immediately comment on the matter.

The development comes 10 days after President Donald Trump signed an executive order creating a framework for the federal government to review the national security risks of the most advanced AI systems before they are publicly released. Under the order, AI developers can voluntarily submit their systems for review for up to one month before launch.