Wednesday's announcement was made during an Iranian military exercise, during which forces staged what they described as an “enemy attack” with rocket launchers, navy helicopters and drones.
It included missiles with a range of 600 kilometres, the semi-official Tasnim news agency reported, but gave no further details on the weapons. Iran recently said a new cruise missile with a 1,000-km range, the Abu Mahdi, had entered service.
The US sent more warplanes and a guided missile destroyer last month in response to Iran's increased activity in the strait.
Pentagon spokeswoman Sabrina Singh told reporters the Department of Defence “is increasing our presence and ability to monitor the [Strait of Hormuz] and surrounding waters.”
About a fifth of the world's crude oil and oil products passes through the strait, between Iran and Oman, making it the world's most important oil chokepoint.
Iran attempted to seize two commercial tankers last month, which the UK Maritime Component Command, an arm of the British military, described as “unacceptable harassment.”
Tehran has seized at least five commercial vessels in the past two years and has harassed several others, the US Navy claimed.
Such operations are viewed as an effort to best the West following the reimposition of US sanctions and the collapse of the 2015 nuclear deal in 2018.
New Iranian weapons
The announcement of the Abu Mahdi cruise missile follows a series of new Iranian weapon system unveilings. Last month, Iran said it was in possession of a new hypersonic missile with a claimed range of 1,400km.
Billboards in Tehran, in Farsi, Hebrew and Arabic, advertised the new weapon with the words “400 seconds to Tel Aviv”.
Hypersonic missiles travel at more than five times the speed of sound, or Mach 5. While most ballistic missiles already travel in excess of this speed on a fixed trajectory, military experts say hypersonic missiles are able to manoeuvre, meaning anti-missile systems such as the US Patriot struggle to anticipate their movement.
Hypersonic missiles give enemy forces only seconds to react to the coming threat.
The capability has become highly coveted and Russia, China and the US. Increasingly, Japan, France and India are investing in the technology.
Russia claims to have used the first hypersonic missile in combat in Ukraine, saying its Kinzhal missiles have struck targets while flying at Mach 10.
US experts say the missile was not truly hypersonic and the US said on May 10 that a Patriot system in Ukraine shot one of them down.
According to the US Department of Defence, however, the overall Iranian missile threat does not come from any one system but the size of "its missile arsenal, which is characterised by increasing numbers, as well as increases in accuracy, range and lethality".
The Pentagon report said: "Iran has the largest ballistic missile force in the Middle East.”