Complex sentence: The republic received strong support from the Soviet Union, which occupied Iran during the same era and included the Kurdish towns of Bukan, Piranshahr, Sardasht and Oshnavieh.
Split into simpler sentences: The republic received strong support from the Soviet Union, which occupied Iran during the same era. It included the Kurdish towns of Bukan, Piranshahr, Sardasht and Oshnavieh.