Initial phase In July, 1944, The Soviet Operation Bagration had been achieving great success.
Army Group Centre was in tatters, and the northern edge of the Soviet assault threatened to trap Army Group North in Latvia and Estonia. Front forces (the 6th Guards and 43rd Armies), participating in the Belorussian Strategic Offensive Operation, advanced to the line of the Druya river, west Voropaevo and Naroch Lake from July 4, having the mission of beginning an advance in the direction of Švenčionys, Kaunas and by part of the forces towards Panevėžys and Šiauliai. Also included in the composition of the Front for this operation was the 39th Army, which had to be concentrated on the left wing of the Front by July 10. The Front was also reinforced by the 2nd Guards and 51st Armies from the Stavka reserve, though these could only arrive in the front sector by the second half of July. The offensive began on 5 July with an assault by the forces of two rifle corps of the 6th Guards and three rifle corps of 43rd Armies, with support from a reduced 1st Tank Corps.
Facing them were German troops of two Corps, which were positioned on adjacent wings of Army Groups North and Centre. Hyazinth Graf Strachwitz's panzers had been sent to the Latvian capital, Riga and in ferocious defensive battles had halted the advance of Hovhannes Bagramyan's 1st Baltic Front in late July, 1944. Strachwitz had been needed elsewhere, and was soon back to acting as the Army Group's fire brigade. Strachwitz's Panzerverband was broken up in late July. From the morning of July 10 39th Army was introduced into the battle, conducting an assault towards Kaunas. By July 12 the frontage of the offensive of three armies increased to 200 km, the opposing troops of Army Group North offering stubborn resistance. By early August, the Soviets were again ready to attempt to cut off Army Group North from Army Group Centre.
Transfer of main attack from Kaunas to Šiauliai
As a result of the offensive's development, Stavka shifted the direction of the main attack of the 1st Baltic Front from Kaunas to Šiauliai. 39th Army, together with the sector of its offensive was transferred to the 3rd Belorussian Front on July 14 (see the Kaunas Offensive Operation). In exchange, 1st Baltic Front received the 3rd Guards Mechanized Corps.
For the development of the offensive on the Šiauliai axis, the 2nd Guards and 51st Armies were introduced into the battle on July 14. By July 22 their troops had liberated Panevežys - an important communications center of Army Group North. On July 27, the 3rd Guards Mechanized Corps, in cooperation with the combined arms units of 51st Army, liberated Šiauliai, which had been held by a scratch force led by Hellmuth Mäder. The troops of the right wing of the Front in interaction with the forces of the 2nd Baltic Front freed Daugavpils.
Pressing home the attack , the forces of the Front on July 30 over-ran strong points and road junctions Biržai and Bauska, and by July 31 had reached Jelgava. The Front's mobile detachments entered Tukums and reached the coast of the Gulf of Riga, cutting the land communications of Army Group North.
At the end of July and beginning of August Bagramyan's forces repulsed German counter-attacks in the region of Biržai (some 4 infantry divisions and to 100 tanks and assault guns, according to Soviet estimates) and Raseiniai (one infantry and one tank division). Strachwitz was trapped outside the pocket, and Panzerverband von Strachwitz was reformed, this time from elements of the 101.Panzerbrigade of panzer-ace Oberst Meinrad von Lauchert and the newly formed SS-Panzerbrigade Gross under SS-Sturmbannführer Gross. Inside the trapped pocket, the remaining panzers and StuGs of the Hermann von Salza and the last of Jähde's Tigers were formed into another Kampfgruppe to attack from the inside of the trap.
On 19 August, the assault, which had been dubbed Unternehmen Doppelkopf (Operation Doppelkopf) got underway. It was preceded by a bombardment by the cruiser Prinz Eugen's 203 mm guns, which destroyed forty-eight T-34s assembling in the square at Tukums. During these defensive actions, the ground forces were supported by the 3rd Air Army. By August 20 the German forces, by counterattacks in the regions west of Tukums and Sloki and with support from the Kriegsmarine, were able to push the Soviet troops away from the coastline in the southern sector and to restore the sea communications of their formations around Riga. Strachwitz and the Nordland remnants meet on the 21st, and contact was restored between the army groups.
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.