On 22nd June 1941 the German 6th Army (Reichenau) and 1st Panzer Group (Kleist) duly attacked along the Lutsk-Rovno axis with the objective of seizing Lutsk, Rovno, Dubno and Ostrog. Within 18 hours of the start of the German invasion elements of the 4th, 15th, 22nd and 9th Mechanised Corps started moving to either blocking positions or counterattack positions. In the next three days there followed a series of meeting engagements between the various mechanised corps closing in and the panzer corps trying to break out. Within 24 hours the Soviets had committed six full mechanised corps, an additional mechanised division, a full cavalry corps and two full rifle corps (the 36th and 37th) to counter-attack the German forces in what is known as the Lutsk-Rovno-Dubno-Lvov border battle. Nowhere is there more evidence that the Soviet pre-war plan was to hold the Western Miliary Districts with echeloned defences, and then repulse and destroy an invader in those districts.
By 25th June the 3rd Panzer Corps’ (Manteuffel) 13th and 14th Panzer Divisions had secured Lutsk. However on 26th June the main Soviet counter-attack began with the aim of cutting off and destroying the 14th Panzer Corps’ (Wietersheim) 16th Panzer Division and 48th Panzer Corps’ (Kempf) 11th Panzer Divisions. Of all the Soviet counter-attacks in late June 1941, this one came the closest to achieving the pre-war plan of isolating and destroying a large invading mobile force. The situation was saved by several German infantry divisions moving up and two panzer divisions counter-attacking the flanks of the various Soviet attack groups. By 28-29th June the Soviet position began to deteriorate rapidly as they ran low on fuel and ammunition, and the whole left flank of the Soviet line had effectively collapsed by 1st July. It is estimated that at least 2 280 Soviet tanks were completely lost from 22nd June to 1st July 1941 in the Lutsk-Rovno-Dubno-Lvov border battle. This means the Southwestern Front irrecoverably lost at least 42% of its initial tank strength in the first 10 days of the war. Meanwhile to the south of this battle the German 17th Army (Stulpnagel) attacked eastwards with two infantry and one mountain corps, pushing back the Soviet 6th and 26th Armies, and had reached Lvov and the Dniester River (south of Lvov) by 30th June.
In the meantime V Fliegerkorps / Luftflotte 4 struggled to attain air superiority in this sector which is unsurprising given they had a 3.2 to 1 inferiority in combat aircraft. The Luftwaffe losses in this sector were initially relatively heavy, but by early July 1941 Luftflotte 4 had achieved air superiority over the south-western axis of the front and was able to conduct serious interdiction operations against the Red Army’s Southwestern Front.
Starting on 1st July the German-Rumanian forces on the Rumanian border started their offensive operations against Southern Front (although several minor exchanges had occurred prior to this date). The Axis forces included the German 11th Army (Schobert, with seven German and four Rumanian infantry divisions) organised into three infantry corps, and the Rumanian 3rd and 4th Armies (under Antonescu). 11th German Army faced a daunting task: its three infantry corps had immediately to fan out and attack independently, while crossing two major rivers, and against a dug in and alerted enemy. To make maters worse, 11th Army’s entire armoured support consisted of only one assault gun battalion (21 assault guns) and elements of the 1st Rumanian Armoured Division (one regiment with 126 R-2 light tanks). In the north, 11th Infantry Corps was to cross the Prut River near Lipkany and attack the junction between the Soviet 12th and 18th Armies, while the 3rd Rumanian Army attacked the 12th Army. In the centre, 30th Infantry Corps was to cross the Prut near Stefanesti and advance on Mogilev-Podolski against the Soviet 18th Army. In the south, 54th Infantry Corps was to cross the Prut just north of Jassy, strike at the junction between the 18th and 9th Army, and advance on Dubossary. In the far south the 4th Rumanian Army was to assault the Soviet 9th Army and advance on Odessa.
The initial axis objective was to ‘recapture’ Bessarabia, obtain as many bridgeheads over the Dniester River as possible, and advance into Southern Front’s south flank and rear. Initially the going was slow because the German-Rumanian attacks were launched over the Prut River, without adequate armour support, and against a ready enemy in fortified positions. Despite this, by 4th July the Southern Front’s 18th and 9th Armies were being pushed back, with the 18th Army experiencing great difficulty retreating across the Dniester River as no permanent bridges were left. The 30th Infantry Corps rapidly established a bridgehead around Mogilev-Podolski (by 5th-6th July) which started creating a potential salient around the Soviet forces further north. In this salient were the Soviet 6th, 12th, 18th and 26th Armies. At around the same time the Rumanian 4th Army had fought its way across the lower Prut and was advancing on Odessa.
Although the German-Rumanian forces performed extremely well, it has to be said that they possibly would not have achieved their goals if the Soviet 12th Army’s 16th Mechanised Corps and the 9th Army’s 18th Mechanised Corps had not already been ordered northwards by Southwestern Front in order to counter-attack the advance by 1st Panzer Group. These mechanised corps, along with the 2nd Mechanised Corps still in 9th Army, would possibly have been able to counter-attack and eliminate any German-Rumanian bridgeheads over the Dniester because the latter were operating with insignificant armour and barely adequate air support. However this may not have been the case: it is very significant that when 2nd Mechanised Corps (with 489 tanks including 60 T-34 and KVs) and 48th Rifle Corps attacked the 11th Army’s 54th Infantry Corps building a bridgehead over the Prut north of Jassy on 3rd-4th July, they were beaten back. This is especially significant because 54th Infantry Corps had only one Rumanian and two German infantry divisions, and no armour at all.
Around 4th July Army Group South’s commander, Gerd non Rundstedt, foresightedly decided to split the efforts of 6th Army and 1st Panzer Group in two diverging directions once Zhitomir and Berdichev had fallen. It was generally against the principles of mobile armoured warfare to do this, but it must have been apparent to Rundstedt that Southwestern Front’s main deployment would be to stop a direct assault on Kiev. As Southwestern Front still had formidable armoured as well as infantry reserves, and Army Group South’s forces were already heavily committed, a direct assault on Kiev would be very difficult and costly. Accordingly he ordered 3rd Panzer Corps to assist 6th Army’s ‘northern group’ to advance on Kiev, while 14th and 48th Panzer Corps and 6th Army’s ‘southern group’ were to turn south from Berdichev towards Pervomaisk and Kirovograd. The aim of the latter group was to trap Soviet forces under pressure from the 17th and 11th Armies further south.
In early July the German 6th Army’s 17th and 51st Infantry Corps advanced eastwards towards Korosten in the difficult terrain of the southern Pripet Marshes, while 3rd Panzer Corps and 29th Infantry Corps advanced eastwards towards Zhitomir. These forces were heading towards Kiev and drove a wedge between 5th and 6th Armies. Further south the 48th and 14th Panzer Corps reached the area around Berdichev on 7th-8th July and captured the city after a brief battle. At the same time the German 17th Army’s three corps continued to push the Soviet 6th and 26th Armies back towards Tarnopol and Proskurov. This caused the Soviet 12th Army to retreat rapidly eastwards to prevent 17th Army encircling it from the north. On the southern wing the Soviet 18th and 9th Armies continued to resist and counter-attack 11th Army at Mogilev-Podolski and around Kishinev, although by 8th July the 11th Army had firmly established its bridgeheads across the Dniester River.