The 'Vilnyus Offensive Operation' was a Soviet part of the third phase of the 'Belorussian Strategic Offensive Operation', otherwise known as 'Bagration', which was the Soviet summer offensive of 1944, designed to encircle and take Vilnyus, the main city of German-occupied Lithuania (5/13 July 1944).

The 'Vilnyus Offensive Operation' was the sixth of the 11 elements together constituting 'Bagration', the others being the 'Vitebsk-Orsha Offensive Operation' (23/28 June), the 'Mogilev Offensive Operation' (23/28 June), the 'Bobruysk Offensive Operation' (24/29 June), the 'Polotsk Offensive Operation' (29 June/4 July), the 'Minsk Offensive Operation' (29 June/4 July), the 'Siauliai Offensive Operation' (5/31 July), the 'Białystok Offensive Operation' (5/27 July), the 'Lublin-Brest Offensive Operation' (18 July/2 August), the 'Kaunas Offensive Operation' (28 July/28 August) and the 'Osovets Offensive Operation' (6/14 August).

Such were the pace and depth of the first stages of 'Bagration' that by 1 July Generalfeldmarschall Walter Model, commanding Heeresgruppe 'Mitte', had become convinced that the most easterly line his command could attempt to hold was that between Baranovichi and Molodechno. Here Model felt that his forces could expect to gain some advantage from the occupation of earthwork defences and trenches which had survived from World War I, but Model also informed Adolf Hitler he would need to be reinforced by several divisions from Generaloberst Georg Lindemann’s Heeresgruppe 'Nord' in order to defend Molodechno. Model’s greatest concern was for the left flank of his army group for, in the area between the right flank of Heeresgruppe 'Nord', which was 'nailed' to Polotsk by Adolf Hitler’s specific order, and the left flank of Generaloberst Georg-Hans Reinhardt’s 3^rd Panzerarmee in the area to the north-east of Minsk, there had opened a gap which was now in the order of 50 miles (80 km) wide. Moreover, a gap almost as wide as this separated the right flank of the 3^rd Panzerarmee and the left flank of Generaloberst Kurt von Tippelskirch’s 4^th Army, under the command of Generalleutnant Vincenz Müller between 30 June and 7 July, in the area of Molodechno. Model rightly appreciated that the strategic and operational situation was such that the 3^rd Panzerarmee could be encircled or merely swept away any time the Soviets were prepared to make the effort: this would leave the road to Riga and the Baltic coast completely exposed.

Although Model branded it as nothing more than a 'futile experiment', Hitler insisted that Heeresgruppe 'Nord' hold Polotsk as the area from which to strike to the south-west and re-establish contact with 3^rd Panzerarmee. Lindemann reported that with two divisions, which was all the strength he could spare if his flank was to retain Polotsk, he could not undertake an effective attack. Then on 3 July Lindemann was authorised to fall back a short distance from Polotsk, but nonetheless continued to insist that he could not attack. Hitler dismissed him and appointed Generaloberst Johannes Friessner, commander of the Armeeabteilung 'Narwa', as his successor.

While a large part of the Soviet force was still employed in the reduction of the German pocket in the area to the east of Minsk following the 'Minsk Offensive Operation', the Soviet high command decided at this stage to exploit the situation along the northern breach in the German defensive line by aligning major mobile formations toward the major traffic centre of Vilnyus in the eastern part of Lithuania. For the German high command, the retention of Vilnyus was essential as its loss would render it all but impossible to re-establish a sustainable overland link between the two German army groups, and to hold the Soviet forces outside East Prussia and away from the south-east coast of the Baltic Sea.

The Stavka issued a new order to the 3^rd Belorussian Front on 4 July, mandating that the front develop its offensive toward Molodechno and Vilnyus with the object of taking the latter no later than 10 July, and also force crossings of the Niemen river. General Leytenant Vasili D. Kryuchenkin’s 33^rd Army was transferred from the 2^nd Belorussian Front to provide the 3^rd Belorussian Front with the strength it needed to attain these objectives.

The German defence in the north central part of the Eastern Front was still in comparative disarray after the 'Minsk Offensive Operation'. Remnants of the General Kurt von Tippelskirch’s [4^th Army which had escaped the encirclement, and units of Generalleutnant Karl Decker’s 5^th Panzerdivision (reorganised into an extemporised Kampfgruppe but later redesignated as General Dietrich von Saucken’s XXXIX Panzerkorps fell back in an effort to establish a defence to the east of Molodechno, which was an important rail junction, but Marshal Pavel A. Rotmistrov’s 5^th Guards Tank Army was able to cut the route between there and Minsk on 3 July.

As noted above, Model had arrived at the conclusion, based on previous experience, that having reached their first major objective, the Soviets would pause for several days, in order to resupply and regroup, as they had advanced 125 miles (200 km), which was greater than their usual limit on one issue of supplies. Model was wholly mistaken in reaching this conclusion, for while the Soviets had indeed reached their first major objective, the Stavka had ordered that the offensive be carried farther to the west on a broad front without pause. General Hovhannes Kh. Bagramyan’s 1^st Baltic Front was to advance toward Dvinsk, General Ivan D. Chernyakovsky’s 3^rd Belorussian Front was to press forward to Molodechno and thence via Vilnyus and Lida to the Niemen river, and General Konstantin K. Rokossovsky’s 1^st Belorussian Front was to drive forward to Baranovichi and thence to the west toward Brest-Litovsk. General Polkovnik Georgi F. Zakharov’s 2d Belorussian Front was to remain where it was and mop up the encircled German forces in the area of Minsk.

Chernyakhovsky ordered that his main mobile exploitation forces, namely the 5^th Guards Tank Army and General Leytenant Nikolai S. Oslikovsky’s III Guards Cavalry Corps, press ahead with their advance from Minsk on 5 July in the direction of Vilnyus, with the object of reaching the city by the following day: these formations were to encircle Vilnyus from the south and north respectively. The infantry divisions of General Leytenant (from 15 July General Polkovnik) Nikolai I. Krylov’s 5^th Army were ordered to follow in the mobile formations' wake and close with them as swiftly as possible. To the south, General Leytenant Ivan I. Lyudnikov’s 39^th Army was ordered to advance toward Lida, and General Polkovnik Kuzma N. Galitsky’s 11^th Guards Army was to press forward on the front’s centre.

As the Soviets launched their Vilnyus operation, the German forces comprised the southern flank of Reinhardt’s 3^rd Panzerarmee in the form of General Gerhard Matzky’s XXVI Corps, Generalmajor Rainer Stahel’s garrison of Vilnyus, and the remnants of the 4^th Army in the form of von Saucken’s XXXIX Panzerkorps, Generalmajor Helmuth Weidling’s Sperrgruppe 'Weidling') and Generalleutnant Theodor Tolsdorff’s 340^th Volksgrenadierdivision. The Soviet forces comprised Chernyakhovsky’s 3^rd Belorussian Front with General Leytenant Kuzma N. Galitsky’s 11^th Guards Army, General Leytenant Nikolai I. Krylov’s 5^th Army, General Leytenant Vasili D. Kryuchenkin’s 33^rd Army, General Leytenant Nikolai Ye. Berzarin’s (later General Leytenant Ivan I. Lyudnikov’s) 39^th Army, General Leytenant Vasili V. Glagolev’s (later General Leytenant Piotr G. Shafranov’s) 31^st Army and Rotmistrov’s 5^th Guards Tank Army, all supported by General Polkovnik Timofei T. Khryukin’s 1^st Air Army.

Soviet reports suggested that their northern-flank formations advanced to schedule, though noting that there was some resistance from scattered remnants of the destroyed VI Corps (commanded by General George Pfeiffer until his death in an air attack on 28 June) of the 3^rd Panzerarmee, but stated that the 11^th Guards Army in particular encountered strong German resistance and was on several occasions counterattacked. The 5^th Panzerdivision was unable to hold Molodechno, however, and the 5^th Army was able to advance to the outskirts of Vilnyus by 8 July, while the 5^th Guards Tank Army encircled the city from the south, thereby trapping the garrison. Another significant rail junction, Lida was captured by the III Guards Cavalry Corps on the evening of 8 July after the German defenders, who were for the most part low-grade but infamously brutal Waffen-SS units of SS-Obergruppenführer und Generalleutnant der Waffen-SS Curt von Gottberg’s Kampfgruppe 'von Gottberg' and SS-Brigadeführer und Generalmajor der Waffen-SS Bronislav Kaminski’s Waffen-Sturmbrigade 'RONA' abandoned their positions in trench lines dating from World War I, despite reinforcement by the Sperrgruppe 'Weidling', which abandoned its attempt to hold Vilnyus on 9 July.

In overall terms, the Soviets had driven forward altogether more rapidly than Heeresgruppe 'Mitte' could deploy its inadequate forces even to attempt a stand. Thus Soviet troops had passed through the 'narrows' to the south and east of Molodechno by 6 July, and the 3^rd Belorussian Front reported that it now possessed total freedom of movement toward Vilnyus. Generaloberst Walter Weiss’s 2^nd Army managed to commit sufficient formations around Baranovichi to check the Soviet advance for a few days, but one Panzer division and one Hungarian cavalry division could in no way bring to a halt four Soviet tank corps backed by infantry. Baranovichi fell to the Soviets on 8 July, as did Lida, the road and rail junction to the west of the Nalibocka forest.

By stretching its front to the west, Heeresgruppe 'Nord' had been able to reduce the gap to the 3^rd Panzerarmee to some 20 miles (32 km). Friessner was planning an attack to the south with three divisions, but the 1^st Baltic Front’s 4^th Shock Army and 6^th Guards Army started to press toward Dvinsk and thus tied down everything on the army group’s flank. Friessner then proposed as a 'small solution' that General Paul Laux’s 16^th Army could withdraw to the 'Litauen-Linie', which was being rapidly improvised between Kraslava (to the east of Dvinsk) and Ostrov, but Hitler refused to countenance a withdrawal of anything more than half of this distance.

During the battle for the city of Vilnyus, Krylov’s 5^th Army and Rotmistrov’s 5^th Guards Tank Army engaged the German garrison of the Festung 'Vilnyus' (399^th Grenadierregiment and 240^th Artillerieregiment of Generalleutnant Siegfried Hass’s 170^th Division, 1067^th Grenadierregiment, one battalion of the 16^th Fallschirmjägerregiment, the anti-tank battalion of Generalleutnant Albrecht Wüstenhagen’s 256^th Division and a miscellany of other units) under the command of Stahel, who was a Luftwaffe officer. The 35^th Guards Tank Brigade initially took the airfield, defended by the paratrooper battalion, and then there began bitter street-by-street fighting as the Soviet forces battled to reduce the defence.

On 12 July the garrison’s parent formation, namely the 3^rd Panzerarmee, launched a counterattack. Generalleutnant Rudolf Freiherr von Waldenfels’s 6^th Panzerdivision, organised into Major Walter Pössl’s Kampfgruppe 'Pössl' and Major Dr Paul Stahl’s Kampfgruppe 'Stahl', attacked to the east from outside the encirclement: Reinhardt and Waldenfels personally accompanied the advance group. The opposing Soviet forces, taken by surprise and hampered by extended lines of supply, were not able to hold the cordon and some of the 6^th Panzerdivision's units were able to advance some 31 miles (50 km) to link with forward elements of the Vilnyus garrison.

There followed a fierce battle on the banks of the Neris river as men of the Polish Home Army sought, without success, to stop the relief force. In the city itself, a Soviet attack on the morning of 13 July managed to split the German forces into two pockets centred around the prison and the observatory, but some 3,000 Germans escaped through the corridor opened by the 6^th Panzerdivision before Soviet forces closed the gap. Even so, something in the order of 13,000 German troops were lost (8,000 killed and 5,000 taken prisoner according to Soviet estimates) as the city was finally captured toward the evening of 13 July.

Despite the Soviet forces' success, Rotmistrov’s commitment of a tank corps in costly urban fighting combined with earlier disagreements with Chernyakhovsky resulted in his replacement as commander of 5^th Guards Tank Army by General Polkovnik Vasili T. Vosky.

While the Germans did not succeed in their aim of holding Vilnyus as a Festung (fortress), their sturdy defence helped to stop the Soviet forces' drive to the west for a few days: most importantly, it tied down the 5^th Guards Tank Army, which had been instrumental in the initial successes of the Soviet forces in 'Bagration'. This delay gave German forces a chance to re-establish something resembling a continuous defence line farther to the west, although this new continuous front line could be held for only a short time. Without the traffic network dependent on Vilnyus, the German position in the southern part of the Baltic states was no longer tenable. By the end of July, the 3^rd Belorussian Front was ordered to conduct the 'Kaunas Offensive Operation' and so further extend the gains made in 'Bagration'.