Iran began construction of a missile assembly facility close to Sirjan with Israeli assistance in 1978 as part of "Operation Flower."[1] However, this may or may not be the same Sirjan as the present facility, as yet another complex was completed in cooperation with North Korea that produces liquid fuels and structural components for ballistic missiles.[2]

Sources:
[1] Yonah Alexander and Milton M. Hoenig, The New Iranian Leadership (London: Praeger Security International, 2008), p. 177.
[2] Trita Parsi, Treacherous Alliance: the Secret Dealings of Israel, Iran and the United States (New Haven: Yale University Press, 2008), p. 75.