The objectives of the rival resistance movement, the Chetniks, were the retention of the Yugoslav monarchy, ensuring the safety of ethnic Serb populations, and the establishment of a Greater Serbia through the ethnic cleansing of non-Serbs from territories they considered rightfully and historically Serbian. Relations between the two movements were uneasy from the start, but from October 1941 they degenerated into full-scale conflict. To the Chetniks, Tito's pan-ethnic policies seemed anti-Serbian, whereas the Chetniks' royalism was anathema to the communists. In the early part of the war Partisan forces were predominantly composed of Serbs. In that period names of Muslim and Croat commanders of Partisan forces had to be changed to protect them from their predominantly Serb colleagues. After the German retreat forced by the Soviet-Bulgarian offensive in Serbia, North Macedonia, and Kosovo in the autumn of 1944, the conscription of Serbs, Macedonians, and Kosovar Albanians increased significantly. By late 1944, the total forces of the Partisans numbered 650,000 men and women organized in four field armies and 52 divisions, which engaged in conventional warfare. By April 1945, the Partisans numbered over 800,000. Name The movement was consistently referred to as the "Partisans" throughout the war. However, due to frequent changes in size and structural reorganizations, the Partisans throughout their history held four full official names: National Liberation Partisan Detachments of Yugoslavia (June 1941 – January 1942) National Liberation Partisan and Volunteer Army of Yugoslavia (January – November 1942) National Liberation Army and Partisan Detachments of Yugoslavia (November 1942 – February 1945). Increasingly from November 1942, the Partisan military as a whole was often referred to simply as the National Liberation Army (Narodnooslobodilačka vojska, NOV), whereas the term "Partisans" acquired a wider sense in referring to the entire resistance faction (including, for example, the AVNOJ). Yugoslav Army – on 1 March 1945, the National Liberation Army was transformed into the regular armed forces of Yugoslavia and renamed accordingly. The movement was originally named National Liberation Partisan Detachments of Yugoslavia (Narodnooslobodilački partizanski odredi Jugoslavije, NOPOJ) and held that name from June 1941 to January 1942. Because of this, their short name became simply the "Partisans" (capitalized), and stuck henceforward (the adjective "Yugoslav" is used sometimes in exclusively non-Yugoslav sources to distinguish them from other partisan movements). Between January 1942 and November 1942, the movement's full official name was briefly National Liberation Partisan and Volunteer Army of Yugoslavia (Narodnooslobodilačka partizanska i dobrovoljačka