Both the British and the Soviets agreed to leave Iran within 6 months of the end of the war. During the war, however, many US training forces moved in to beef up the Iranian military and this proved a sticking point. Throughout northwest Iran, the eastern part of Syria and the northern part of Iraq, the Kurdish militia (the Peshmerga), with battle experience and Soviet arms, resisted, creating the People’s Republic of Kurdistan. Less than a year after WWII , one of the first in a series of proxy battles would take place as two Iranian battalions attempted to smash a Peshmerga strongpoint near Mamashah, the high ground overlooking the Kurdish capital of Mahabad. No less than the life of the Kurdish Republic was on the line.
After weeks of trying to force a decisive engagement, the Iranians finally cornered significant Peshmerga forces in territory they could not abandon. The Soviets had struck a deal with Iran on oil leases in the Caspian and pulled out, leaving their erstwhile allies in a lurch. Both sides knew that the high ground before the capital was crucial and the Iranians hit them with their best troops – trained in the US.