The Department of Defense has officially informed Anthropic’s leadership that the company and its products have been designated a supply chain risk, effective immediately, according to a senior department official.

“From the very beginning, this has been about one fundamental principle: the military being able to use technology for all lawful purposes,” the official told CNBC. “The military will not allow a vendor to insert itself into the chain of command by restricting the lawful use of a critical capability and put our warfighters at risk.”

Anthropic is the only American company ever to be publicly named a supply chain risk, as the designation has traditionally been used against foreign adversaries. The label will require defense vendors and contractors to certify that they don’t use Anthropic’s models in their work with the Pentagon.

The formal designation marks the latest development in the ongoing clash between Anthropic and the Pentagon, which have been at odds over how the startup’s artificial intelligence models, known as Claude, can be used. Even so, the DOD has used Anthropic’s models to support the U.S. military’s operations in the ongoing conflict in Iran, as CNBC has previously reported.