via the "People's committees", organized to act as civilian governments in areas of the country controlled by the communists, even limited arms industries were set up. At the very beginning, Partisan forces were relatively small, poorly armed and without any infrastructure. They had two major advantages over other military and paramilitary formations in former Yugoslavia: A small but valuable cadre of Yugoslav volunteers in the Spanish Civil War who, unlike anyone else at the time, had experience with modern war fought in circumstances quite similar to those of World War II Yugoslavia They were founded on ideology rather than ethnicity, which meant the Partisans could expect at least some levels of support in any corner of the country, unlike other paramilitary formations whose support was limited to territories with Croat or Serb majorities. This allowed their units to be more mobile and fill their ranks with a larger pool of potential recruits. Occupying and quisling forces, however, were quite aware of the Partisan threat, and attempted to destroy the resistance in what Yugoslav historiographers defined as seven major enemy offensives. These are: The First Enemy Offensive, the attack conducted by the Axis in autumn of 1941 against the "Republic of Užice", a liberated territory the Partisans established in western Serbia. In November 1941, German troops attacked and reoccupied this territory, with the majority of Partisan forces escaping towards Bosnia. It was during this offensive that tenuous collaboration between the Partisans and the royalist Chetnik movement broke down and turned into open hostility. The Second Enemy Offensive, the coordinated Axis attack conducted in January 1942 against Partisan forces in eastern Bosnia. The Partisan troops once again avoided encirclement and were forced to retreat over Igman mountain near Sarajevo. The Third Enemy Offensive, an offensive against Partisan forces in eastern Bosnia, Montenegro, Sandžak and Herzegovina which took place in the spring of 1942. It was known as Operation TRIO by the Germans, and again ended with a timely Partisan escape. This attack is mistakenly identified by some sources as the Battle of Kozara, which took place in the summer of 1942. The Fourth Enemy Offensive, against "Republic of Bihać", also known as the Battle of the Neretva or Fall Weiss (Case White), a conflict spanning the area between western Bosnia and northern Herzegovina, and culminating in the Partisan retreat over the Neretva river. It took place from January to April 1943. The