East Prussian Offensive The East Prussian Offensive was a strategic offensive by the Red Army against the German " Wehrmacht " on the Eastern Front ( World War II ) . It lasted from 13 January to 25 April 1945 , though some German units did not surrender until 9 May . The Battle of Königsberg was a major part of the offensive , which ended in victory for the Red Army . The East Prussian Offensive is known to German historians as the " Second " East Prussian Offensive . The " First " East Prussian Offensive ( also known as the Gumbinnen Operation ) , took place from 16 – 27 October 1944 , and was carried out by the 3rd Belorussian Front under General I . D . Chernyakhovsky as part of the Memel Offensive of the 1st Baltic Front . The Soviet forces took heavy casualties while penetrating into east - northern part of Poland , and the offensive was postponed until greater reserves could be gathered . The East Prussian Offensive . The main thrust of the offensive was to be conducted by the 3rd Belorussian Front under Ivan Chernyakhovsky . His forces were tasked with driving westwards towards Königsberg , against the defensive positions of the 3rd Panzer Army and 4th Army , the northern armies of General Georg - Hans Reinhardt ' s Army Group Centre . From the north , on Chernyakhovsky ' s right flank , General Hovhannes Bagramyan ' s 1st Baltic Front would attack the positions of the 3rd Panzer Army on the Neman , as well as crushing its small bridgehead at Memel . Chernyakhovsky ' s left flank would be supported by the 2nd Belorussian Front of Marshal Konstantin Rokossovsky , which was initially ordered to push north - west to the Vistula , through the lines of the 2nd Army , thereby sealing off the whole of East Prussia . Opening of the offensive . The Soviet offensive began on 13 January with a heavy preparatory bombardment . At first , the Red Army made disappointing progress ; the 3rd Belorussian Front gained just 1 . 5 km on the first day . Over the next five days , the Soviets managed to advance only a further 20 km , at the cost of very high casualties . Eventually , after almost two weeks of severe fighting , the Red Army began making steady progress , although again , this came at the price of high losses ; the defenders having the advantage of substantial fortifications in the Insterburg Gap east of Königsberg , and around Heilsberg . Over the next few days , the 3rd Panzer Army of General Erhard Raus was largely destroyed or withdrew into Königsberg , while General Friedrich Hossbach ′ s 4th Army began to find itself outflanked . Against fierce resistance , Rokossovsky attacked across the Narew on 14 January ; on 20 January , he received orders to swing the axis of his advance northward toward Elbing . This sudden change of direction caught Reinhardt and Hossbach by surprise ; on Rokossovsky ' s right flank , the 3rd Guards Cavalry Corps captured the major town of Allenstein on 22 January , threatening the rear of Hossbach ' s formation . On 24 January , Rokossovsky ' s leading tank units had reached the shore of the Vistula Lagoon , severing land communications with the rest of German armed forces for the entire 4th Army along with several divisions of the 2nd Army which were now trapped in a pocket centered on East Prussia . On the same day , Hossbach began to pull his units back from the fortified town of Lötzen — a center of the East Prussian defence system — and through a series of forced marches attempted to break out westward . In the meantime , Chernyakhovsky had succeeded in rolling up the defences from the East , pushing the remnants of the 3rd Panzer Army into Königsberg and Samland . On 28 January , Bagramyan ' s forces captured Memel ; the remnants of the three divisions defending the town were evacuated and redeployed in Samland to reinforce the defence there . The Siege of Königsberg and the Heiligenbeil pocket . With the remnants of Army Group Centre effectively contained , Soviet forces could concentrate on reducing the German forces in Pomerania and eliminating any possible threat to the northern flank of their eventual advance on Berlin . Reinhardt and Hossbach — who had attempted to break out of East Prussia and save their troops — were relieved of command , and the Army Group ( redesignated Army Group North ) was placed under the command of General Lothar Rendulic . Reinhardt gave up his command with the words " There is nothing more to say " . Raus and the staff of the destroyed 3rd Panzer Army were assigned to a new formation . The defending forces , in the meantime , were besieged in three pockets by Chernyakhovsky ' s armies : Even after this time , German forces continued to resist on the Vistula Spit , the long sandbar enclosing the Vistula Lagoon , until the end of the war .