After completing the Vilnius Offensive Operation, the troops of the 3rd Belorussian Front were engaged in intense fighting with German forces on the approaches to the Neman river during the second half of July, and were preparing for the continuation of the offensive. They were resisted by formations and units of the Third Panzer and Fourth Armies of the German Army Group Centre, under the command of Field-MarshalWalter Model. Towards the end of July, German units concentrated in the direction of Kaunas, according to Soviet estimates, included elements of 10 infantry and 2 tank divisions, 2 infantry brigades and 30 separate regiments and battalions. Stavka assigned to the forces of the Front the mission of pressing home the attack on the Kaunas axis not later than 1–2 August, through assaults by the 39th Army together with the 5th Guards Tank Armyfrom the north, and the 5th and 33rd Armies from the south to occupy Kaunas – the most important defensive position on the approaches to East Prussia. The plan called for the Red Army troops to advance to the borders of East Prussia by the 10 August and assume a defensive configuration in preparation for advancing into East Prussia. As with the parallel defence against the Belostock Offensive to the south, Model concentrated on a holding / delaying action using the few units available to him. The German Order of Battle for mid-July showed units from a large number of divisions in the area, but many of these were fragments that had escaped from the encirclement of the bulk of Army Group Centre in the previous phases of Operation Bagration; see deployments below.
On 28 July the forces of the Front went over to the offensive, and by the end of 29 July they had advanced 5–17 km. By July 30 the German resistance on the approaches to the Neman was broken. In the 33rd Army sector, the 2nd Guards Tank Corps was introduced into the breakthrough: their rapid advance to Vilkaviškis threatened the German forces before Kaunas with encirclement and the Germans were forced to retreat. Using the success of the Tank Corps, the troops of the 33rd Army entered and secured Vilkaviškis and the railway station of Mariampolė on 31 July. Troops of the 5th Army broke into Kaunas and on the morning of 1 August took control of it. Towards the beginning of August the forces of the Front advanced up to 50 km and subsequently enlarged the breakthrough to 230 km, liberating more than 900 villages, townships, towns and small cities. During August, Raus' Third Panzer Army was reinforced and mounted a counter-offensive on the Front's northern flank in Operation Doppelkopf. German troops also delivered a series of strong counter-attacks south-west and west of Kaunas. Having countered these, the 3rd Belorussian Front's troops moved a further 30–50 km and advanced towards deliberately prepared German fortified positions on the line east of Raseiniai and Kybartai - Suwałki. From 29 August on the orders of Stavka, the Front went over to the defensive. As a result of the Kaunas operation the forces of the 3rd Belorussian Front reached the eastern borders of East Prussia.
