Mujahideen forces caused serious casualties to the Soviet forces, and made the war very costly for the Soviet Union. In 1989 the Soviet Union withdrew its forces from Afghanistan. In February 1989 the seven Sunni mujahideen factions formed the Afghan Interim Government (AIG) in Peshawar, led by Sibghatullah Mojaddedi, as an attempt for a united front against the DRA. The AIG became a failure, partly because it could not solve the differences between the factions; partly because of limited public support as it excluded the Iran-backed Shia mujahideen factions, and the exclusion of supporters of ex-King Mohammed Zahir Shah; and the mujahideen's failure in the Battle of Jalalabad in March 1989.