Until early 1943, the Soviet partisans focused primarily on survival deep behind enemy lines, with their activity limited mostly to sabotage and diversion rather than armed struggle against German forces and collaborationist police units. During this early period various Soviet partisan groups also collaborated with the local Polish resistance of ZWZ, later renamed the AK. The Polish underground was established in the area in the fall 1939. Polish resistance was both anti-Nazi and anti-Soviet; their attitude represented the fact that both powers had invaded Poland, and Polish citizens suffered from Soviet terror just as they did from Nazi terror. There was no love lost between Polish and Soviet resistances, as Joseph Stalin's goal was to prevent a reemergence of an independent Poland after the war.