US President Donald Trump announced Friday that he was instructing every federal agency to “immediately cease” use of Anthropic’s AI tools. The move comes after Anthropic and top officials clashed for weeks over military applications of artificial intelligence.

“The Leftwing nut jobs at Anthropic have made a DISASTROUS MISTAKE trying to STRONG-ARM the Department of War,” Trump said in a post on Truth Social.

Trump said that there would be a “six month phase out period” for agencies using Anthropic, which could allow time for further negotiations between the government and the AI startup.

The Pentagon and Anthropic did not immediately respond to requests for comment.

Shortly after the President’s announcement, defense secretary Pete Hegseth said that Anthropic would also be designated a “supply chain risk,” a move normally reserved for foreign businesses considered a danger to American national security. The designation will bar the US military and its contractors and suppliers from working with the AI company.

Hegseth also lashed out at Anthropic and its CEO, Dario Amodei, over the company’s refusal to agree to its demands. “Cloaked in the sanctimonious rhetoric of ‘effective altruism,’ they have attempted to strong-arm the United States military into submission—a cowardly act of corporate virtue-signaling that places Silicon Valley ideology above American lives,” Hegseth wrote on X.

The Department of Defense has sought to change the terms of a deal struck with Anthropic and other companies last July to eliminate restrictions on how AI can be deployed and instead permit “all lawful use” of the technology. Anthropic objected to the change, claiming that it could allow AI to be used to fully control lethal autonomous weapons or to conduct mass surveillance on US citizens.

The Pentagon does not currently use AI in these ways, and has said it has no plans to do so. However, top Trump administration officials have voiced opposition to the idea of a civilian tech company dictating military use of such an important technology.

Anthropic was the first major AI lab to work with the US military, through a $200 million deal signed with the Pentagon last year. It created several custom models known as Claude Gov that have fewer restrictions than its regular ones. Google, OpenAI, and xAI signed similar deals around the same time, but Anthropic is the only AI company currently working with classified systems.

Anthropic’s model is available through platforms provided by Palantir and Amazon’s cloud platform for classified military work. Claude Gov is currently largely used for run-of-the-mill tasks, like writing reports and summarizing documents, but it is also used for intelligence analysis and military planning, according to one source familiar with the situation who spoke to WIRED on condition of anonymity because they are not authorized to discuss the matter publicly.

In recent years, Silicon Valley has gone from largely avoiding defense work to increasingly embracing it and eventually becoming full-blown military contractors. The fight between Anthropic and the Pentagon is now testing the limits of that shift. This week, several hundred workers from OpenAI and Google signed an open letter supporting Anthropic and criticizing their own companies’ decisions to remove restrictions on military use of AI.

In a memo sent to OpenAI staff today, CEO Sam Altman said that the company agreed with Anthropic and also viewed mass surveillance and fully autonomous weapons as a “red line.” Altman added that the company would try to agree to a deal with the Pentagon that would let it continue working with the military, The Wall Street Journal reported.