Iran's Revolutionary Guard launched an attack involving missiles, speedboats, helicopters, and commandos on a mock-up of a US aircraft carrier.
Drones separately targeted the bridge of the fake aircraft carrier as it floated in the Strait of Hormuz, according to a state TV report.
The report did not immediately air footage of the launches or the drone attack, nor did it identify the missiles used in the drill.
A semiofficial news agency close to the Guard published a graphic overnight that photoshopped the image of an American carrier into the shape of a casket.
Iranian commandos fast-roped down from a helicopter onto the replica in the footage aired Tuesday from the exercise called "Great Prophet 14." Anti-aircraft guns opened fire on a target drone near the port city of Bandar Abbas.
State television footage also showed a variety of missiles being fired from fast boats, trucks, mobile launchers and a helicopter, some targeting the fake carrier. A commander said the Guard, a force answerable only to Khamenei, planned to fire "long-range ballistic missiles" as well during the drill that continued Wednesday.
During the drill American troops were put on alert at Al-Dhafra Air Base in Abu Dhabi in the United Arab Emirates and Al-Udeid Air Base, the forward headquarters of the U.S. military's Central Command in Qatar, the military said. Troops sought cover during that time.
"The incident lasted for a matter of minutes and an all clear was declared after the threat ... had passed," said U.S. Army Maj. Beth Riordan, a Central Command spokeswoman.
Both bases are hundreds of miles away from where Iran put the replica aircraft carrier.
Al-Dhafra also is temporarily home to five French-built Rafale fighter jets on their way to India for that country's air force.
Other footage from the exercise aired by Iran's state television showed fast boats encircling the mock-up carrier, kicking up white waves in their wake.
While Iran's naval forces are dwarfed by the U.S. Navy, its commanders practice so-called "swarm" tactics aimed at overwhelming the U.S. carriers that pass through the strait on their way in and out of the Persian Gulf.
It was not immediately clear if all the footage was from Tuesday, as one overhead surveillance image that appeared to be shot by a drone bore Monday's date. The exercise had been expected as satellite photos released Monday showed the fake carrier being moved into place by a tugboat.