Updated

The U.S. Navy is putting underwater drones through wartime-style drills as part of international mine-clearing exercises in the Persian Gulf following similar maneuvers by Iran.

The U.S.-led exercises, which began last week, include operations by the unmanned SeaFox devices, which are equipped with sonar and an explosive charge designed to shoot and destroy mines. It is part of the Navy's plans to increasingly deploy automated surveillance and protection systems, including aerial drones.

Navy commanders insist the exercises, comprising more than 41 nations, are not intended solely against possible Iranian threats. But Iran has previously warned it could block critical Gulf oil routes in retaliation for Western sanctions over Tehran's nuclear program.

In apparent response to the U.S.-led drills, Iran last week staged its own minesweeping operations.