The White House has asked OpenAI and Anthropic to withhold their newest artificial intelligence systems from the U.K. government’s model-testing pipeline until U.S. officials complete their own review. This directive raises the stakes for American AI labs that have been sharing early versions of frontier models with Britain’s AI Security Institute.

A senior administration official and a person familiar with the matter reported that the outreach came from the Office of the National Cyber Director. The goal is to let the U.S. government test first and harden domestic systems before any partner access, as reported by Politico. The official framed the approach as consistent with how the administration is handling cutting-edge releases, stating, "Because they’re American companies and this has been our policy with every new frontier model that comes out."

U.S. seeks early access control

Anthropic appears to be complying with the request. The company did not provide its Claude Mythos 5.1 system to the U.K. institute, instead limiting availability to U.S.-based entities. In its announcement, Anthropic said the model was "only available to a set of U.S. organizations." The company added, "We’re coordinating with the U.S. government to expand access to a broader set of domestic and international partners as quickly as possible," while declining additional comment.

In a letter earlier this month to a U.K. parliamentary committee, AI Security Institute Director Henry de Zoete acknowledged the institute did not get access to Anthropic’s latest model. De Zoete noted the agency still has advance access to some top-tier systems and cited pre-release testing of OpenAI’s GPT-6 Astra.

The White House push comes as officials weigh how to manage increasingly capable models after tests found some systems were able to break into external targets, including an Australian government website. The report also highlighted warnings from former engineers and other prominent AI figures about severe risks if development speeds ahead without sufficient safeguards.

International scrutiny and domestic capacity gaps

Britain has promoted the AI Security Institute, founded in 2023, as a key tool for voluntary pre-release evaluations and as part of its pitch to shape international AI rules. U.K. Prime Minister Andy Burnham said this week AI will be "at the heart" of the country’s G20 presidency next year, while also telling the U.N. General Assembly the institute was "working hand in glove with the U.S. and the leading labs on AI safety."

At the U.N. Security Council on Wednesday, U.K. Foreign Secretary Ed Miliband argued governments need frontier systems to be "rigorously tested" and said, "The leading AI companies have actually committed to provide this visibility. It’s really, really important, and it is an offer that we and they should follow through."

On the U.S. side, lawmakers and the White House are seeking more funding for the Commerce Department’s Center for AI Standards and Innovation, known as CAISI. The center is operating without a permanent director and is being asked to assess more models despite having only a few dozen technical staff members. OpenAI said this week that CAISI should take a leading role in setting international methods for tracking AI progress and safety in coordination with other national institutes, including the U.K.’s AI Security Institute.

What the numbers show

The divergence between the U.K.'s diplomatic emphasis on collaborative safety frameworks and the U.S.'s operational restriction on model access highlights a growing tension between international regulatory alignment and national security protocols. While the U.K. positions its institute as a global hub for voluntary evaluation, the U.S. is leveraging its domestic review capacity as a gatekeeper, potentially slowing the pace of cross-border safety assessments despite stated commitments to cooperation.

OpenAI CEO Sam Altman appeared before the UN Security Council to advocate for shared artificial intelligence safety standards while preserving technological development. He positioned himself as a "pragmatic centrist," arguing against excessive concentration of control among a few companies.

The UN General Assembly’s current session focuses on fears that AI may become uncontrollable. Secretary-General António Guterres recently warned of AI dangers and called for global cooperation, a proposal President Donald Trump rejected as a "global scheme."

Strategic positioning and regulatory stance

OpenAI representatives stated the company does not plan to endorse any specific international regulatory body. Instead, it aims to advocate for AI safety and democratic control. The company suggested the UN could facilitate discussions on standards, while individual countries pursue their own regulatory frameworks through democratic processes.

Industry participation and safety frameworks

Anthropic CEO Dario Amodei participated remotely by video. Both Altman and Amodei have pushed for binding government regulations and safety standards. Amodei recently published an article titled "We Must Pace the Frontier," calling for a slowdown in development to allow safety, alignment, interpretability, and testing efforts to keep pace with advancing technology.

Amodei’s proposed framework includes:

• Independent third-party evaluators
• Coordination among AI companies in democratic countries
• Global agreements on AI safety standards
• Limits on the pace of development

What the numbers show

The divergence between Guterres’ call for global cooperation and Trump’s rejection of it as a "global scheme" highlights the geopolitical friction surrounding AI governance. While industry leaders like Altman and Amodei advocate for unified standards, the political landscape remains fragmented, with OpenAI explicitly avoiding endorsement of a single international body to accommodate national sovereignty.