"The Iranians are making great efforts to obtains a significant number of missiles," according to Tal Inbar, head of the Space Research Center near Tel Aviv.
"They already talk of how one of the ways they will overcome (Israel's) missile defense systems is by firing salvoes of missiles."
Iran's current production capabilities are not known with any great exactitude, but these have been concerned primarily with the manufacture of Shehab-3 intermediate range ballistic missiles.
The Israelis, who see Iran's nuclear and missile programs as an existential threat, claim that Iran's missile development is more advanced than the West believes.
At present, the liquid-fueled Shehab is the mainstay of the Islamic Republic's strategic missile forces. Tehran is believed to have deployed 100-200 of these weapons, which have an estimated range of 1,250 miles.
But with the successful May 20 launch of a new ballistic missile, the solid-fuel Sajjil-2, with a reported range of 1,200 miles, Western specialists believe that Iran is now on the threshold of producing a new generation of long-range missiles.
It is likely that Iran will concentrate its production capabilities on the new missile. Solid-fuel missiles can be launched faster than liquid-fueled systems, which can take up to an hour to fuel.
Thus solid-fuel missiles are harder to detect in launch mode than liquid-fueled weapons, and thus less vulnerable to pre-emptive strikes.
A third ballistic missile, the Ashura, also solid-fueled, was unveiled in 2007 and test-fired in 2008. The Jerusalem Post reported on May 18 that the two-stage Ashura was believed to have entered production, possibly to replace the Shaheb-3.
However, some Western experts believe that the two-stage Sajjil-2 -- Sajjil-1 was test-fired in November 2008 -- may be another name for the Ashura, intended to confuse the United States and Israel about Iran's missile program.
Still, recent assessments of Iranian capabilities by two major think tanks have sought to downplay the missile threat posed by Tehran.
The EastWest Institute in New York, a non-partisan organization that focuses on global challenges, said Iran would not have a long-range weapon capable of delivering nuclear warheads for many years.
The six U.S. and six Russian scientists who authored the report released May 19 said that Iran might develop a missile with a nuclear warhead and a 1,200-mile range in six to eight years.
But they concluded that it was "virtually impossible" to predict how long it would take to produce a modern intercontinental ballistic missile.
Without considerable outside assistance and technology, it would be "at least 10 to 15 years," they said, noting that there was no evidence that the Tehran regime has even decided to go for an intercontinental ballistic missile.
The International Institute for Strategic Studies in London noted that with the Sajjil launch, "Iran appears to have established the industrial infrastructure and technological foundation to begin efforts, on its own, to support the eventual development, design and production of much larger, more powerful rocket motors.
"If so, these developments are similar to those achieved by Tehran in the nuclear arena, where Iranian engineers have mastered the ability to enrich uranium sufficiently to power a civilian nuclear reactor, and established the wherewithal to produce highly enriched uranium for a nuclear bomb in the future, if so desired."
However, the analysis cautioned that considerable obstacles remain before Iran can achieve assembly-line production of ballistic missiles.
"Before being able to deploy the Sajjil missile, Iran would first need to establish a production line for solid-fuel rocket motors to strict performance criteria," it said.
"This would require many static test firings and test launches over the next three to five years. … Missile advances will not occur suddenly."