Iran's Revolutionary Guards fired missiles carrying cluster warheads at the start of ten days of military manoeuvres today, state television reported.
Tehran had said the manoeuvres, which will include drills in the Gulf and Sea of Oman, were to show off "defensive strength".
Days earlier, navies led by the United States practiced blocking the transport of weapons of mass destruction in the Gulf.
Tensions between Iran and Western powers are high as the latter try to agree a draft UN sanctions resolution aimed at forcing Tehran to scale back atomic work they fear may be used to make bombs. Iran says its aims are purely peaceful.
Footage showed six missiles being fired from mobile launchers and leaving long vapour trails as they soared into the air above the desert near the holy city of Qom in central Iran.