Iran's state TV says the country's navy has kicked off its two-day annual drill near the strategic Strait of Hormuz.
The strait is a key waterway through which a third of all oil traded by sea passes and it has been the scene of previous confrontations between the United States and Iran.
The drill does not involve Iran's powerful Revolutionary Guard, a paramilitary force the U.S. Navy often criticizes for harassing its vessels.
Monday's report says the air force and ground forces will also participate in the exercise in the Sea of Oman and parts of the Indian Ocean near the strait.