- Range and types -
Its short- and medium-range missiles can fly up to 2,000 kilometres (1,200 miles), bringing archfoe Israel and US military bases in the region within range.
The most powerful of its 40 different types of missiles are the Ghadr F and Sejil-2 -- both 17 metres (56 feet) in length with a 2,000-kilometre range -- and Ghadr H and Imad which can travel some 1,700 kilometres.
The Imad was the first missile tested after Iran's nuclear deal with world powers in July 2015.
Tehran's testing of that missile led to new US sanctions imposed on January 17, 2016, a day after international sanctions were lifted as the nuclear deal came into effect.
Iran says it has also developed solid fuel-powered missiles.
- Russian S-300 and Iran's Bavar-373 -
Iran's advanced S-300 air defence system, delivered by Russia following the nuclear deal after several years of delay, finally became operational last March.
A domestically manufactured air defence system, Bavar-373, which Iranian officials say is "more advanced than the S-300", is due to be tested soon.
- Number -
No reliable public information exists on the number of missiles in Iran's arsenal.
Tehran has launched mass production of domestically-produced missiles, the latest of which was the Sayyad-3, an anti-drone and anti-fighter missile with a range of 120 kilometres.
A senior Revolutionary Guard commander said in a speech in January 2016 that the paramilitary group has a huge number of missiles, without disclosing figures.
"Hundreds of long tunnels are full of missiles ready to fly to protect your integrity, independence and freedom," said General Hossein Salami.
- Underground silos -
In October 2015, state television aired unprecedented footage of an underground missile base referred to as "missile city" made up of huge tunnels.
Last May, the Guards announced the launch of a third underground missile factory.
- Application -
In June 2017, the Revolutionary Guards fired off short-range precision missiles into Syria to avenge deadly attacks in Tehran claimed by the Islamic State jihadist group.
It was the country's first known missile attack beyond its own borders since the Iran-Iraq war of 1980-1988.
- Sanctions -
Tehran's missile programme has long been the target of Western sanctions and controversy.
A UN Security Council resolution endorsing the nuclear deal states: "Iran is called upon not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons".
Iran, which denies the pursuit of an atomic programme for military purposes, insists none of its missiles are "designed to carry a nuclear warhead", leaving them outside the scope of the 2015 deal.
The missile programme is purely for defensive aims, the Islamic republic says.
- Satellite rocket -
The latest anti-Iran Congress sanctions bill awaiting US President Donald Trump's signature target Tehran's missile programme.
The US Treasury on July 29 singled out six companies owned or controlled by Shahid Hemmat Industrial Group (SHIG), which it said was central to Iran's missile programme, a day after Tehran tested a rocket for launching a satellite into orbit.
"Space launch vehicles use technologies that are closely related to those of an intercontinental ballistic missile and this launch represents a threatening step by Iran," according to Treasury Secretary Steven Mnuchin.
Iran said the launch vehicle can propel a satellite weighing 550 pounds (250 kilograms) to an altitude of 500 kilometres.