Iran is building a fortified missile storage and launch complex for at least fifteen Shahab 3 missiles outside Khorramabad (near the Iraq border in the Zagros mountains). It is called the Imam Ali missile base and is run by the Revolutionary Guard Corps. The Shahab 3 missile is basically 1960s technology, with the addition of GPS guidance. Russian and North Korean missile technology has been obtained to make the Shahab 3 work. This has resulted in a missile that apparently will function properly about 80 percent of the time, and deliver a warhead of about one ton, to a range of some 1,300 kilometers, to within a hundred meters of where it was aimed. By world standards, this is a pretty effective weapon.
The Shahab 3 normally travels on a tractor trailer rig that can also raise the missile into a launch position. But it takes several hours to fuel the missile and otherwise prepare it for launch. Thus the Iranian tactics are to drive the missiles and fuel trucks out to a remote location for erecting and launching. The Khorramabad base also shows signs of silo construction.
Iran is believed to have been building Shahab 3s since 2004, even though they continue to refine the design, and conduct test firings. Iran is believed to have 50-100 Shahab 3s, and is building about one a month. There are indications that production has increased. Israel appears to be the main target. Iran has threatened Israel with destruction, rather openly of late. Shahab 3's could be fired with high explosive warheads, and hit, with enough accuracy, to kill mostly Jews, and not Israeli Arabs or Palestinians. Iran also has chemical (nerve gas) warheads, and Israel has threatened nuclear retaliation if they get hit by chemical warheads.
A longer range version, the Ghadr, has been in the works for several years. It has a longer (1,800 kilometers) range, and can be readied for launch in less than an hour, rather than several hours for the Shahab 3. There have been several well observed (by foreign intel agencies) tests in the last two years.