Anthropic is at odds with the Department of Defense over how its artificial intelligence models should be used, and its work with the agency is “under review,” a Pentagon spokesperson told CNBC.

The 5-year-old startup was awarded a $200 million contract with the DOD last year. As of February, Anthropic is the only AI company that has deployed its models on the agency’s classified networks and provided customized models to national security customers.

But negotiations about “going forward” terms of use have hit a snag, Emil Michael, the undersecretary of war for research and engineering, said at a defense summit in Florida on Tuesday.

Anthropic wants assurance that its models will not be used for autonomous weapons or to “spy on Americans en masse,” according to a report from Axios.

The DOD, by contrast, wants to use Anthropic’s models “for all lawful use cases” without limitation.