The Al Hussein Scud derivative has a range of 600km.
About SCUDs:
http://www.fas.org/nuke/guide/russia/theater/r-11.htm "The SCUD-D SS-1e featured an improved guidance system, possibly incorporating active radar terminal homing, and a wider choice of warheads than its predecessors. This missile has a range of about 700 km. Initially operational in the 1980s, it may not have been deployed by former Soviet ground forces.
More:
http://www.pbs.org/wgbh/pages/frontline/gulf/weapons/scud.html "The Iraqis had four versions: Scud itself (180-km range), longer-range Scud (half warhead weight, extra range attained by burning all propellant immediately rather than steadily through the flight of the missile), Al Hussein (650-km, attained by reducing warhead weight to 250 kg and increasing the fuel load by 15 percent), and Al Abbas (800-km, achieved by reducing warhead weight to 125 kg, with 30 percent more fuel). Al Abbas could be fired only from static launchers; all of the others could be fired from mobile or static sites. Only the original Scud and the minimally modified version were particularly succesful."