The original Turkmen groups arrived from the east of the Caspian Sea into northwestern Afghanistan at various periods, particularly after the end of the 19th century when the Russians moved into their territory. They established settlements from Balkh Province to Herat Province, where they are now concentrated; smaller groups settled in Kunduz Province. Others came in considerable numbers as a result of the failure of the Basmachi revolts against the Bolsheviks in the 1920s.