Iran's Revolutionary Guard has launched large-scale naval and air defence drills near a strategic Gulf waterway in which dozens of speedboats attacked a replica of a US aircraft carrier.
The drill, named Great Prophet 9, was held near the Strait of Hormuz, through which one fifth of the world's oil passes. Iran's regular army carried out naval drills near the strait in December.
State TV showed footage of missiles fired from the coast and the fast boats striking the mock aircraft carrier.
The drills, which also included shooting down a drone and planting undersea mines, were the first to involve a replica of such a vessel.
"American aircraft carriers are very big ammunition depots housing a lot of missiles, rockets, torpedoes and everything else," the Guard's navy chief, Admiral Ali Fadavi, said on state TV, adding that a direct hit by a missile could set off a large secondary explosion.
Last month, Fadavi said his force is capable of sinking US aircraft carriers in the event of war.
General Mohammad Ali Jafari, the Guard's chief commander, said the drills send a "message of [Iran's] might'' to "extraterritorial powers," a reference to the US.
Commander Kevin Stephens, the spokesman for the US Navy's 5th Fleet in Bahrain, said the Iranian naval exercises began a few days ago and have had no effect on maritime traffic.
Stephens said the Americans were monitoring the drills, but downplayed the simulated attack on the carrier, saying the US military was "not concerned about this exercise".
"We're quite confident of our naval forces' ability to defend themselves," he said. "It seems they've attempted to destroy the equivalent of a Hollywood movie set."
Iran is currently negotiating an agreement over its disputed nuclear programme with the US and five other world powers. The two sides hope to reach a framework agreement next month and a final deal in June.
Western nations have long suspected Iran is covertly seeking a nuclear weapons capability, charges denied by Tehran.