Iran's missile programme has hit the headlines again with the announcement that it has successfully launched a new medium-range rocket, capable of reaching Israel and southern Europe.
However, the launch may have taught Western observers little they did not already know about the scope and potential firepower of Tehran's arsenal.
Iran says its missile development programme is solely for scientific, surveillance or defensive purposes but there are concerns in the West and among Iran's neighbours that the rockets could be used to carry nuclear weapons.
Analysts have previously suggested that Iran staged missile tests to reinforce the message that it was ready to hit back if Israel or the US - or both - launched any kind of military strike on its nuclear facilities.
Western analysts are guarded in many of their assessments of Iran's missile fleet, which is difficult to evaluate without access to concrete information.
However, London-based defence analyst Christopher Pang told the BBC that despite the attention it attracts, Iran lags far behind in its missile development.
A report on Iran's nuclear capabilities, released earlier in May 2009 by the EastWest Institute think tank, said that "with the components and technologies it now has, Iran could hypothetically build missiles with a range of 3,000km or more".
But the group said it would be at least another 10 to 15 years before Iran developed advanced intermediate-range ballistic missiles or intercontinental ballistic missiles to carry nuclear warheads.
Below are details of some of Iran's key missile systems as they are viewed by Western-based analysts.
The Shahab-3, launched in July 2008, is the longest-range missile Iran has successfully tested in public. Conventional wisdom in the US suggested the Shahab-3 could strike targets up to 1,300km (807 miles) away, but Iran's military boasted in the test that the Shahab had a range of 2,000km (1,240 miles).
This longer range could indicate that the July test involved a newer, modified version of the Shahab-3, perhaps the rumoured Shahab-3b, which Iran says would have a range of up to 2,500km.
Either range would be enough to put targets in the Gulf and in Israel within reach, although the longer range version could be sited further from Israeli air bases.
The Shahab-3, classed as a medium range ballistic missile (MRBM), is widely thought to be based on the technology behind North Korea's No Dong missiles, but is produced and developed in Iran.
Many believe Iran is attempting to develop Shahab missiles to carry nuclear warheads, but analysts say perfecting this ability would be a complex process.
SAJJIL-1 AND SAJJIL-2
Iran first tested a Sajjil rocket in November 2008, describing it as a highly accurate, surface-to-surface weapon.
Iran said the Sajjil-2 made use of "advanced technology"
Defence Minister Mohammed Najjar said at the time that Sajjil was a two-stage defensive missile with an "extraordinarily large capability". But analysts says surface-to-surface missiles are primarily defensive.
The Sajjil is believed to have a range of about 2,000km (1,240 miles), giving it one of the longest ranges of Iran's arsenal. It runs on solid fuel, which is considered to give a more accurate delivery than liquid fuel rockets.
Its high launching speed means several can be fired in quick succession, says GlobalSecurity.org, a US-based website.
In May 2009, Iran said it had successfully tested a Sajjil-2 missile. Announcing the launch, President Mahmoud Ahmadinejad said the missile used "advanced technology" and had "landed exactly" on its intended target.
The launch came as campaigning opened in Iran's presidential elections and was designed to reinforce the idea of national unity and strength, said Christopher Pang.
"It is meant to demonstrate that Iran is incrementally progressing to more advanced, sophisticated and most importantly, indigenous missile technology," he said.
Mr Pang said the launch also sent a signal to the UN as it considers imposing a fourth round of sanctions on Iran, that Tehran will not be deterred from continuing its missile development programme.
SHAHAB-1 and SHAHAB-2
The predecessors to the Shahab-3, these are Scud-type missiles with shorter ranges than the more modern weapon.
The earlier Shahab missiles are less accurate and less deadly
The missiles are based on North Korean and/or Libyan technology. Iran is thought to have up to 150 Shabab-2 missiles and up to 300 of the Shahab-1, according to GlobalSecurity.org.
These earlier versions of the Shahab missile are smaller and carry lighter fuel and payloads than the Shahab-3.
Scud technology is now decades old, and early versions of the missile were first used by Iran during its war with Iraq in the 1980s. Saddam Hussein also fired Scud-type missiles at Israel during the 1991 Gulf War, causing damage but little loss of life.
The current Iranian Scud missiles have a maximum range of 500km (310 miles), according to GlobalSecurity.org.
Iran could use smaller, lighter missiles against targets in Afghanistan
The Zelzal, which Iran's Revolutionary Guards also tested in July 2008, is a shorter range missile said to be capable of hitting targets up to about 400km away (250 miles), although figures vary.
The missile is said to have been used against suspected militant training camps in Iraq in the early 2000s, and is thought to have been delivered to the Lebanese militia group Hezbollah. The group has never confirmed or denied that it has the Zelzal.
The other type of missile tested alongside the Shahab-3, the Fateh, or Conqueror, has an even shorter range than the Zelzal, of up to 170km (100 miles).
But while the focus of concerns tends to be on the possibility of a conflict between Iran and Israel, analysts have suggested that shorter-range missiles serve Iran's other strategic interests as well.
Fateh missiles, for example, could be used to target US military interests to the east of Iran, in Afghanistan.
MAXIMUM MISSILE RANGE
Sajjil-1 and 2: 2,000km
Zelzal: up to 400km
Iran launched a Safir rocket in August 2008 and said the tests showed the rocket was capable of carrying a satellite into space.
In February 2009, President Ahmadinejad said Iran had "officially achieved a presence in space" by using a Safir-2 rocket to put its first domestically built satellite, Omid, into a low orbit.
Analysts said the Safir-2 was basically the same as the Shahab-3, meaning each launch could be used to improve the rocket's reliability and so enhance Iran's missile technology.
UK Foreign Office minister Bill Rammell said the "dual applications for satellite launching technology" were a cause for concern.