Throughout the War, the Chetnik movement remained almost completely inactive against the occupation forces, and increasingly collaborated with the Axis, losing its international recognition as the Yugoslav resistance force. After a brief initial period of cooperation, the Partisans and the Chetniks quickly started fighting against each other. Gradually, the Chetniks ended up primarily fighting the Partisans instead of the occupation forces, and started cooperating with the Axis in their struggle to destroy the resistance, receiving increasing amounts of logistical assistance. Mihailović admitted to a British colonel that the Chetniks' principle enemies were "the partisans, the Ustasha, the Muslims, the Croats and last the Germans and Italians" in that order.
At the start of the conflict, Chetnik forces were merely relatively inactive towards the occupation, and negotiated with the Partisans. This changed when these talks broke down, and they proceeded to attack the latter (who were actively fighting the Germans), while continuing to engage the Axis only in minor skirmishes. Attacking the Germans provoked strong retaliation, and the Chetniks increasingly negotiated with them. Negotiations were aided by their mutual goal of destroying the Partisans. This collaboration first appeared during the attack on the Partisan "Užice Republic", where Chetniks played a part in the general Axis attack.
Collaboration with the ItaliansChetnik collaboration with the occupation forces of fascist Italy took place in three main areas: in Italian-occupied (and Italian-annexed) Dalmatia, in the Italian puppet state of Montenegro, and in German and Italian-occupied Slovenia. The collaboration in Dalmatia and parts of Bosnia was the most widespread, however, and the 1941 split between the Partisans and the Chetniks took place earlier in those areas. The Partisans considered all occupation forces the fascist enemy, while the Chetniks hated the Ustaše but balked at fighting the Italians, and had approached the Italian VI Army Corps (General Renzo Dalmazzo, Commander) as early as July and August 1941 for assistance via a Serbian politician from Lika, Stevo Rađenović. In particular, Chetnik leaders (vojvoda-s) Ilija Trifunović-Birčanin and Dobroslav Jevđević were favorably disposed towards the Italians, because they believed Italian occupation over the whole of Bosnia and Herzegovina would be detrimental to the influence of the Ustaše state. For this reason, they sought an alliance with the Italian occupation forces in Yugoslavia. The Italians (General Dalamazzo) looked favorably on these approaches and hoped first to avoid fighting the Chetniks, and then use them against the Partisans, which they thought would give them an "enormous advantage". An agreement was concluded on January 11, 1942 between the representative of the Italian 2nd Army, Captain Angelo De Matteis and the Chetnik representative for southeastern Bosnia, Mutimir Petković, and was later signed by Draža Mihailović's chief delegate in Bosnia, Major Boško Todorović. Among other provisions of the agreement, it was agreed that Italians would support the Chetnik formations with arms and provisions, and would facilitate the release of "recommended individuals" from Axis concentration camps (Jasenovac, Rab...). The chief interest of both the Chetniks and Italians would be to assist each other in combating the Partisan resistance.
In the following months of 1942, General Mario Roatta, commander of the Italian 2nd Army, worked on developing a Policy Directive (Linea di condotta) on relations with the Chetniks, the Ustaše and the Partisans. In line with these efforts, General Vittorio Ambrosio outlined the Italian policy in Yugoslavia: all negotiations with the (quisling) Ustaše were to be avoided, but contacts with the Chetniks were "advisable" - as for the Partisans: "struggle to the bitter end". This meant that General Roatta was essentially free to take action with regard to the Chetniks as he saw fit. He outlined the four points of his policy in his report to the Italian Army General Staff:
To support the Chetniks sufficiently to make them fight against the communists, but not so much as to allow them too much latitude in their own action; to demand and assure that the Chetniks do not fight against the Croatian forces and authorities; to allow them to fight against the communists on their own initiative (so that they can "slaughter each other"); and finally to allow them to fight in parallel with the Italian and German forces, as do the nationalist bands [Chetniks and separatist Zelenaši] in Montenegro.
—General Mario Roatta, 1942
During 1942 and 1943, an overwhelming proportion of Chetnik forces in the Italian-controlled areas of occupied Yugoslavia were organized as Italian auxiliary forces in the form of the "Voluntary Anti-Communist Militia" ("Milizia volontaria anti comunista", MVAC). According to General Giacomo Zanussi (then a Colonel and Roatta's chief of staff), there were 19,000 to 20,000 Chetniks in the MVAC in Italian-occupied parts of the Independent State of Croatia alone. The Chetniks were extensively supplied with thousands of rifles, grenades, mortars and artillery pieces. In a memorandum dated March 26, 1943 to the Italian Army General Staff entitled "The Conduct of the Chetniks", Italian officers noted the ultimate control of these collaborating Chetnik units remained in the hands of Draža Mihailović, and contemplated the possibility of a hostile reorientation of these troops in light of the changing strategic situation. The commander of these troops was vojvoda Ilija Trifunović-Birčanin, who arrived in Italian-annexed Split in October 1941 and received his orders directly from Mihailović in the spring of 1942.
The Chetnik-Italian collaboration lasted until the Italian capitulation on September 8, 1943, when Chetnik troops switched to supporting the German occupation in forcing the Partisans out of the coastal cities which they liberated upon the Italian withdrawal. The German 114th Jäger Division even incorporated a Chetnik detachment in its advance to the Adriatic.
Collaboration with the NDHSee also: Independent State of Croatia and Ustaše
Representatives of the Chetniks, Ustaše, and Croatian Home Guard meet in Bosnia.After the 1941 split between the Partisans and the Chetniks in Serbia, the Chetnik groups in central, eastern, and northwestern Bosnia found themselves caught between the German and Ustaše (NDH) forces on one side and the Partisans on the other. In early 1942 Chetnik Major Jezdimir Dangić approached the Germans in an attempt to arrive at an understanding, but was unsuccessful, and the local Chetnik leaders were forced to look for another solution. The Chetnik groups were in fundamental disagreement with the Ustaše on practically all issues, but they found a common enemy in the Partisans, and this was the overriding reason for the collaboration which ensued between the Ustaše authorities of the Independent State of Croatia (NDH) and Chetnik detachments in Bosnia. The first formal agreement between Bosnian Chetniks and the Ustaše was concluded on May 28, 1942, in which Chetnik leaders expresseed their loyalty as "citizens of the Independent State of Croatia" both to the state and its Poglavnik (Ante Pavelić). During the next three weeks, three additional agreements were signed, covering a large part of the area of Bosnia (along with the Chetnik detachments within it). By the provision of these agreements, the Chetniks were to cease hostilities against the Ustaše state, and the Ustaše would establish regular administration in these areas. The main provision, Art. 5 of the agreement, states as follows:
As long as there is danger from the Partisan armed bands, the Chetnik formations will cooperate voluntarily with the Croatian military in fighting and destroying the Partisans and in those operations they will be under the overall command of the Croatian armed forces. (...) Chetnik formations may engage in operations against the Partisans on their own, but this they will have to report, on time, to the Croatian military commanders.
—Chetnik-Ustaše collaboration agreement, May 28, 1942
The necessary ammunition and provisions were supplied to the Chetniks by the Ustaše military. Chetniks who were wounded in such operations would be cared for in NDH hospitals, while the orphans and widows of Chetniks killed in action would be supported by the Ustaše state. Persons specifically recommended by Chetnik commanders would be returned home from the Ustaše concentration camps (Jasenovac concentration camp). These agreements covered the majority of Chetnik forces in Bosnia east of the German-Italian demarcation line, and lasted throughout most of the war. Since Croatian forces were immediately subordinate to the German military occupation, collaboration with Croatian forces was, in fact, indirect collaboration with the Germans.