The Seistan Force, originally called East Persia Cordon, was a force of British Indian Army troops set up to prevent enemy infiltration from Persia into Afghanistan during World War I. The force was established to protect British interests in Persia from subversion by German agents, most notably Wilhelm Wassmuss. The force was also tasked to intercept and destroy the Turco-German expedition to Kabul that sought Afghan alliance in the Central war effort and Afghan assistance to war time revolutionary conspiracies in India.