Head of the Revolutionary Guards' aerospace unit, Brigadier General Amir Ali Hajizadeh, told Tasnim news agency: "We are working day and night to protect Iran's security.
"If we see smallest misstep from the enemies, our roaring missiles will fall on their heads."
Iran responded to the new US sanctions - imposed because of the test firing of a ballistic missile - by announcing another military exercise using its missile and radar systems.
The Revolutionary Guards Sepahnews website said that the aim of the military exercise in Semnan province, central Iran, was to "showcase the power of Iran's revolution and to dismiss the sanctions." READ MORE