Iran’s Revolutionary Guards said on Tuesday it had captured a U.S. uncrewed submarine at the entrance to the Strait of Hormuz, offering a rare glimpse into how underwater drones are being used in military operations.

Iranian state media said the vessel was a Dive-LD, a large autonomous underwater vehicle built by California defense firm Anduril. The 19-foot (5.8-metre) submersible can carry out missions including mine countermeasures, seabed mapping, intelligence gathering and the inspection of underwater infrastructure such as cables and pipelines, the company has said.

“We trapped one of the most modern, intelligent and unmanned submarines of the terrorist American army at the entrance to the Strait of Hormuz. This submersible is equipped with the latest technologies,” the Revolutionary Guards Navy said in a statement carried by Iranian state media.

In response, a Pentagon spokesperson said an underwater drone had “malfunctioned more than a day ago.”

“It was surveying regional waters in support of ongoing operations. The defective drone was an older model that neither collected sensitive data nor carried any classified sonar or radar equipment,” the spokesperson said.

Reuters could not independently verify Iran’s claims and the Pentagon did not address them in its statement.

Anduril did not respond to a request for comment.

The U.S. military is investing heavily in unmanned naval systems, including underwater and surface vessels, as it seeks cheaper ways to monitor vast areas of ocean, gather intelligence and track adversary ships and submarines without putting sailors at risk.

According to Anduril’s website, Dive-LD can operate for up to 10 days without returning to base and is designed to dive to depths of as much as 6,000 metres (19,700 feet). Dive-LD units cost about $2.5 million each, U.S. military news site DefenseScoop reported in 2024.