WASHINGTON, D.C.: Iran's Revolutionary Guards said on September 8 that its forces had captured a U.S. unmanned underwater vessel near the entrance to the Strait of Hormuz.

The claim has drawn attention to the growing use of autonomous underwater drones in military operations.

Iranian state media identified the vessel as a Dive-LD, a large autonomous underwater vehicle developed by California-based defense company Anduril. The 19-foot (5.8-meter) underwater craft is designed to carry out a range of missions without an onboard crew.

According to Anduril, the Dive-LD can detect and clear naval mines, map the seabed, and collect intelligence. It can also inspect underwater infrastructure, including pipelines and communication cables.

The Revolutionary Guards Navy said Iranian forces had intercepted the vessel near the Strait of Hormuz and highlighted its advanced technology. "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 force said in a statement carried by Iranian state media.

The Pentagon gave a different account of what happened. A U.S. defense official said an underwater drone had suffered a technical failure more than a day before Iran announced the capture.

The official said the drone had been operating in regional waters as part of ongoing U.S. military activities. The Pentagon also said the vessel was an older model and did not contain sensitive information or classified sonar or radar equipment.

Anduril confirmed that one of its underwater vessels had been lost but downplayed the incident's importance. The company said the Dive-LD was built as an expendable autonomous system intended for operations in dangerous areas, where losing a vehicle could be expected.

The incident highlights the increasing role of unmanned systems in modern naval warfare. The U.S. military has been investing heavily in underwater and surface drones as it looks for less expensive ways to monitor large areas of ocean and gather information.

Unmanned systems can also monitor enemy ships and submarines without putting American sailors directly in danger. Their use is expected to expand as military forces develop more advanced autonomous technology.

Anduril says the Dive-LD can remain at sea for as long as 10 days before needing to return to a base. The vehicle is also designed to operate at depths of up to 6,000 meters (19,700 feet), allowing it to carry out missions far below the ocean surface.

The underwater vehicle is also relatively costly. U.S. military news website DefenseScoop reported in 2024 that each Dive-LD unit cost about US$2.5 million.