The appearance of Greek partisans in those areas persuaded the Italians to allow the formation of these detachments. The Bulgarian plan was to organize them militarily in the hope that Bulgaria would eventually assume the administration there. The appearance of Greek partisans in Western Macedonia persuaded the Italian and German authorities to allow the formation of Slav security battalions led by Bulgarian officers. The initial detachments were formed in early 1943 in the district of Kastoria by Andon Kalchev with the support of the head of the Italian occupation authorities in Kastoria lieutenant Ravalli, who armed the local villages to help combat the growing resistance activity by the ELAS.