The two stretches of Sino-Soviet frontier which lie on either side of the Mongolian Republic differ from each other in at least one important respect: whereas the Soviet population on the eastern stretch is predominantly Russian, or at any rate non-Asian, and faces the solidly Asian population of Manchuria, that of the western stretch is predominantly Turkic-Muslim and faces the predominantly Turkic-Muslim population of the Sinkiang Uighur Autonomous Region formerly known as the Province of Sinkiang.