A picture taken on April 9, 1992 shows a Russian S300 missile burning away from its pad in Priozorsk during a training launch. Russia on December 22, 2008 denied that it was delivering sophisticated S-300 surface-to-air missiles to Iran, following reports it was about to supply the weapons to the US arch-foe.

According to Iran’s Fars news agency, Iran has obtained four S-300PT air-defense missile systems. Fars claimed that this report was first revealed last year by another news agency—one linked to Hezbollah—and that Iran never disputed the story. The report claimed that two of the four systems came from Belarus; details about the source of the other two systems were not provided and have not been reported elsewhere since the Fars claim. Belarus has denied any involvement in such a deal.

In fact, the story begins well before last year. According to a report by Mark Harrington from February 2008 in Jane’s International Defence Review, Belarus and Iran were then finalizing a major arms deal, conceived at an exhibition in Minsk in May 2007 attended by Iranian President Ahmadinejad and other senior Iranian Revolutionary Guard Corps leaders.

Harrington’s sources enumerated many details. For instance, Iran was to purchase two surplus S-300PT (also known as SA-10 “Grumble”) systems, composed of two types of Fakel-class missiles, which had been recently deployed around Minsk. These were to be broken down and transported by air to Iran, covered as ordinary cargo, along with a full complement of spare parts and Belarussian training and maintenance personnel. In addition, at the time of Harrington’s report, Belarussian personnel had already completed the repair and upgrade of two other S-300PT systems already possessed by Iran since the late 1990s. Belarus’ asking price for the entire package totaled $140 million USD. All this was supposedly done without the knowledge of Russia, the original manufacturer.

U.S. intelligence is aware of the threat of the emergence of Iranian S-300 systems. Another Jane’s report highlighted a November 2008 conference at Redstone Arsenal, Alabama, titled “Iranian Surface-to-Air Missile Systems.” Though the content of that meeting is classified, one day of the conference was devoted to a case-by-case review of Iranian systems, which included a 45-minute session titled “SA-20 SAM Systems.” The SA-20 is a more modern, longer-range variant of the S-300 system. Its inclusion in a briefing otherwise focused on known Iranian systems is indicative of a belief—already present in 2008—that the advanced system was likely to soon become operational.

The Heritage Foundation’s Ariel Cohen has explained that Iranian deployment of the S-300 system would be a “game-changer in the Middle East.” Iran’s existing air defense system is outdated and unable to defend against airstrikes targeting its nuclear facilities, but an Iranian-manned S-300 network could significantly restrict the West’s military options—even more than they already are. For example, Israel does not possess aircraft with stealth technology; the S-300 system was designed to defend against primarily conventional warplanes, and its possession by Iran could severely hamper Israel’s ability to strike effectively.

Iran’s announcement creates more questions than answers. If Iran has obtained even the early SA-10 variant of the S-300 system, its air defense capabilities have evolved considerably almost overnight. If Iran obtains the more modern SA-20 variant, American contingency strike plans will surely become even more limited because of that system’s greatly enhanced range, survivability, and capability. However, the intelligence on this subject remains patchy, and in the past, Western planners have demonstrated a great capability to overwhelm Soviet- and Russian- made anti-aircraft missile systems.

Nick Krueger is the Jordan Saunders Intern in the Young Leaders Program at the Heritage Foundation. For more information on interning at Heritage, please visit: http://www.heritage.org/about/departments/ylp.cfm.