The Battle of Königsberg, also known as the Königsberg offensive, was one of the last operations of the East Prussian offensive during World War II. In four days of urban warfare, Soviet forces of the 1st Baltic Front and the 3rd Belorussian Front captured the city of Königsberg, present day Kaliningrad, Russia. The siege started in late January 1945 when the Soviets initially surrounded the city. Heavy fighting took place for control of overland connection between Königsberg and the port of Pillau, however by March 1945 Königsberg was hundreds of kilometres behind the main front line in the eastern front. The battle ended when the German garrison surrendered to the Soviets on 9 April after a three-day assault made their position untenable.