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.
On June 22, 1944, the Soviets launched their main summer offensive (Operation Bagration) in Belarus. Involving 2.5 million soldiers and over 6,000 tanks, the offensive sought to destroy Army Group Center while also preventing the Germans from diverting troops to combat the Allied landings in France. In the ensuing battle, the Wehrmacht suffered one its worst defeats of the war as Army Group Center was shattered and Minsk liberated.