OpenAI has reached an agreement with the US Department of War to deploy its artificial intelligence models on classified cloud networks, CEO Sam Altman announced on Friday, marking a significant expansion of AI use within US military systems.

"Tonight, we reached an agreement with the Department of War to deploy our models in their classified network. In all of our interactions, the DoW displayed a deep respect for safety and a desire to partner to achieve the best possible outcome.," Altman said in a post on X.

The agreement comes amid heightened tensions between the administration of US President Donald Trump and rival AI firm Anthropic over the military use of artificial intelligence.

Trump on Friday said he had ordered all federal agencies to immediately halt work with artificial intelligence lab Anthropic, while allowing a six-month phaseout period for the Defense Department and other agencies currently using the company’s products.

"I am directing EVERY Federal Agency in the United States Government to IMMEDIATELY CEASE all use of Anthropic’s technology. We don’t need it, we don’t want it, and will not do business with them again!" Trump said in a post on Truth Social.

Pentagon chief Pete Hegseth said he was directing the defense department to designate Anthropic a “supply-chain risk to national security.”

"Effective immediately, no contractor, supplier, or partner that does business with the United States military may conduct any commercial activity with Anthropic," Hegseth added in a statement on X.

Detailing the framework of OpenAI’s deal, Altman said the company would implement strict safeguards to ensure its systems operate strictly within agreed parameters.

"AI safety and wide distribution of benefits are the core of our mission. Two of our most important safety principles are prohibitions on domestic mass surveillance and human responsibility for the use of force, including for autonomous weapon systems. The DoW agrees with these principles, reflects them in law and policy, and we put them into our agreement," Altman wrote on X.

"We also will build technical safeguards to ensure our models behave as they should, which the DoW also wanted. We will deploy FDEs to help with our models and to ensure their safety, we will deploy on cloud networks only," he added.

"We are asking the DoW to offer these same terms to all AI companies, which in our opinion we think everyone should be willing to accept. We have expressed our strong desire to see things de-escalate away from legal and governmental actions and towards reasonable agreements," he mentioned.

Altman also added, "We remain committed to serve all of humanity as best we can. The world is a complicated, messy, and sometimes dangerous place."