Anthropic has suspended access to its advanced artificial intelligence models, Fable 5 and Mythos 5, following a US government directive citing national security concerns, the company announced on Friday.
The decision comes only three days after the public launch of Fable 5, a restricted version of the more powerful Mythos 5 model. In a statement published on its website, Anthropic said it received a government order on Friday evening requiring the company to block access to both systems for all foreign nationals, including foreign employees working at Anthropic.
“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 said.
According to reports, the directive was issued by the US Department of Commerce. Anthropic said the government’s letter did not specify the exact reasons behind the move, though the company believes officials became concerned about a potential method of bypassing, or “jailbreaking,” Fable 5’s safety protections.
Fable 5 was introduced earlier this week as a controlled version of Mythos 5, which Anthropic had previously kept from broad public release because of concerns about its exceptional ability to identify software vulnerabilities. Such vulnerabilities can be exploited by cybercriminals to gain unauthorized access to systems.
Mythos 5 has been made available only to a limited number of organizations under strict conditions. Fable 5 was designed to offer similar capabilities while operating within stronger safety restrictions.
Anthropic said it had reviewed the alleged jailbreak technique and concluded that the issue did not provide hackers with capabilities beyond those already available through other publicly accessible AI models. The company also stated that its security testing teams had not discovered any universal method capable of bypassing the model’s safeguards.
“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,” Anthropic said in its statement.
The company warned that applying such a standard across the AI industry could significantly slow the release of future advanced models.
The suspension has also drawn attention overseas. The European Union, which gained access to Mythos 5 earlier this month following discussions with Anthropic, said the development highlighted the importance of reducing dependence on foreign technology providers.
European Commission spokesman Thomas Regnier said officials were assessing the situation, noting that the bloc recently unveiled plans aimed at strengthening Europe’s technological independence in strategic sectors, including artificial intelligence.
The latest development adds to ongoing tensions between Anthropic and the Trump administration. The company has previously opposed the use of its technology in certain defense and surveillance applications, leading to disputes with US authorities and the loss of some government contracts.
For now, Anthropic said it remains committed to complying with the order while working to restore access as quickly as possible if circumstances allow.
