Also in 1921 IMRO created as a satellite organisation the Internal Western Outland Revolutionary Organisation, which operated in the areas of Tsaribrod and Bosilegrad, ceded to Yugoslavia.
They also cross the border to include the dialects or subdialects of the Bulgarian minority in the Western Outlands (the regions of Tsaribrod and Bosilegrad), Bulgarian territories transferred to Serbia by the Treaty of Neuilly as punishment for Bulgarian participation in World War I on the side of the Central Powers.