The Trump administration decision to impose export controls on Anthropic products most powerful AI technology followed a row over the company granting South Korean telecommunications giant SK Telecom access to its Claude Mythos model, according to people familiar with the matter. U.S. officials were concerned about what they claimed were SK Telecom’s ties to China, these sources said.
These concerns appear to have worsened when Amazon then reported vulnerabilities he identified himself in Fable 5 with the White House. Fable 5 is a highly secure version of Mythos that Anthropic released to the public on June 9. Amazon researchers said it was possible to bypass some of Fable 5’s guardrails and access Mythos’ formidable cyber capabilities, although Anthropic and external cybersecurity experts argued that these risks are not unique to Claude.
The confluence of events is what ultimately led the White House to determine that it could not trust Anthropic to safeguard its most advanced AI technology, according to a person close to the administration. On Friday, the Trump administration ordered Anthropic to revoke access to Mythos and Fable 5 for all foreign nationals, including immigrants to the United States.
Rather than block access to its technology based on nationality, a difficult process to implement while maintaining privacy, Anthropic decided it was better to disable access to models altogether. The White House and Anthropic remain in disagreement after days of negotiations to put Claude Mythos and Fable 5 back online.
Anthropic declined to comment. The White House and SK Telecom did not immediately respond to a request for comment. The Washington Post previously reported that Trump administration officials were alarmed to learn that the recipients of the Myth included a “South Korean telecommunications company“, they believed, had ties to China, although the article did not name the company. In response to this information, SK Telecom told a Korean newspaper that “anonymous insider remarks in foreign media lack verified facts and that our company has no connection with China.”
A person close to Anthropic said the company views SK Telecom’s access to Mythos and the vulnerabilities identified by Amazon as separate issues. They noted that the letter the US government sent to Anthropic to demand that it restrict access to Claude Mythos and Fable 5 only to US nationals and not refer to the Korean company or China.
Because Claude Mythos is exceptionally good at identifying software vulnerabilities, Anthropic restricted early access to a small group of trusted organizations through a program called Project Glasswing. Earlier this month, SK Telecom, South Korea’s largest mobile operator, became one of about 150 companies to gain access to Mythos as Anthropic expanded the program.after several weeks of close collaboration» with external experts and the American government.
SK Telecom has injected capital into Anthropic on several occasions, including 100 million dollars investment in 2023 which coincided with the formation of a business partnership develop an AI model adapted to the telecommunications industry. It was one of several Korean organizations to participate in the Glasswing project, alongside Samsung Electronics and the Korea Internet and Security Agency.
Earlier this month, shortly after Anthropic announced the latest expansion of Project Glasswing, the White House asked Anthropic to revoke SK Telecom’s access to Mythos, according to a person close to the AI lab. The company immediately complied, sources told WIRED, and the U.S. government did not threaten to impose export controls on the model at the time.
Although SK Telecom itself does not appear to have large operations in China, it is part of a much larger conglomerate called SK Group, whose subsidiaries maintain numerous business interests in the country, spanning semiconductors, energy and other sectors.
In 2024, SK Telecom generated only about $1.9 million in revenue in China, mainly through investment-related activities, and employed only seven people there, according to its annual report.
But its involvement in China’s telecommunications industry dates back more than 20 years. In 2004, SK Telecom and China Unicom, a state-owned telecommunications operator, formed a joint venture called UNISK to provide wireless Internet and mobile content services in China. This is one of the first joint ventures between a foreign company and a Chinese carrier.
In 2006, SK Telecom invested $1 billion in convertible bonds issued by China Unicom’s Hong Kong-listed unit, which were eventually converted into a stake of around 6.6 percent. But the partnership began to unravel several years later. SK Telecom sold its stake in China Unicom back to the Chinese operator in 2009 for around $1.3 billion, while retaining a small financial interest in the company. In its 2025 annual deposit with the United States Securities and Exchange Commission, SK Telecom listed an investment in UNISK valued at approximately $17 million.
In 2021, the first Trump administration restricted US investment in China Unicom as part of a broader effort targeting Chinese companies that Washington has declared linked to the country’s military and intelligence sectors. In April this year, citing national security concerns, the US Federal Communications Commission proposed banning US telecommunications companies from interconnecting with China Unicom and other Chinese carriers, a move that China Unicom recently warned could disrupt global communications.
Hugo Lowell and Zeyi Yang contributed reporting.