Iran's elite Revolutionary Guards blasted a mock-up of a US aircraft carrier with missiles on Tuesday during military exercises, state television reported.
The annual war games were held near the Strait of Hormuz, a crucial shipping lane for a fifth of global oil output.
The exercises, dubbed "Prophet Mohammed 14th", in the Gulf waters come at a time of high tension between Tehran and Washington.
The US Navy condemned the "irresponsible and reckless behaviour by Iran" and said it was an attempt "to intimidate and coerce".
Footage aired on Iran's state television showed the paramilitary Revolutionary Guard firing a missile from a helicopter, which targeted the mock-up aircraft carrier.
Iran's actions come only days after Tehran accused US fighter jets of harassing an Iranian commercial airliner in Syria's skies.
"What was shown today in these exercises, at the level of aerospace and naval forces, was all offensive," Guards commander Major General Hossein Salami told state television.
"Some surprise equipment and weapons were used, such as long-range ballistic missiles capable of striking offensive floating targets in the distance," General Abbas Nilforoushan, deputy commander for operations, was quoted by the Guards' Sepahnews website as saying.
Tensions have escalated between Tehran and Washington since US President Donald Trump unilaterally withdrew from the landmark Iran nuclear deal in 2018.
The long-standing foes have come to the brink of direct confrontation twice since June 2019, when the Guards shot down a US drone in the Gulf.
Their animosity deepened after Iran's most prominent general, Qasem Soleimani, was killed in a US drone strike near Baghdad airport in January this year.