Nevertheless, "Stavka" knew that Operation Iskra was incomplete, as the corridor it had opened was narrow and was still in range of the German artillery, and the important heights and strong point at Sinyavino remained under German control. This led Zhukov to plan Operation Polyarnaya Zvezda (Polar Star). This much more ambitious offensive operation aimed to decisively defeat Army Group North, but faltered early on. The Soviet forces carried out several other offensives in the area in 1943, slowly expanding the corridor, making other small gains before finally capturing Siniavino in September. However, the city was still subjected to at least a partial siege as well as air and artillery bombardment until January 1944, when the Leningrad-Novgorod Offensive broke through the German lines, lifting the siege completely.