The situation facing Heeresgruppe Süd at X-hour on 22 June 1941 was far more disadvantageous than that faced by either of the other two German army groups. Von Kleist’s Panzergruppe 1 had to conduct an opposed river crossing across the Western Bug into a heavily-defended fortified region, which meant the 6.Armee’s infantry would first have to create a series of bridgeheads before German armour could be committed. Beginning at dawn on 22 June, the 6.Armee used five infantry divisions to conduct multiple crossings across the Western Bug River. The 298.Infanterie-Division, with the help of Brandenburg infiltration troops, managed to seize an intact bridge at Ustilug. German pioneers also succeed in capturing an intact bridge further south, at Sokal. Two Soviet rifle divisions opposed the crossing but were too thinly spread to seriously interfere with the initial bridge seizures. Wasting no time, 6.Armee immediately sent Sturmgeschütz-Abteilung 197 across the Sokal bridge at 0450 hours. In order that von Kleist’s panzers would not be delayed by the use of just two bridges, German pioneers immediately began building pontoon bridges across the river to provide multiple crossing points. Despite the successful crossing of the Western Bug, von Kleist could initially commit only three of his nine motorized divisions to exploit the bridgeheads due to the narrowness of the attack sector and congestion at the two bridges. General der Panzertruppen Ludwig Crüwell’s 11.Panzer-Division crossed the Sokal bridge and pushed past weak resistance nearly 30km by the end of the first day. From Ustilug, the 6.Armee was able to seize the town of Vladimir Volynskii, which opened the way for General der Panzertruppen Friedrich Kühn’s 14.Panzer-Division to push toward Lutsk – Panzergruppe 1’s intermediate objective.
General Leytenant Mikhail P. Kirponos, in command of the Southwestern Front, hurried to his new wartime command post at Tarnopol, but once there he could barely communicate with any of his subordinate forces for the first two days of the war. His headquarters personnel were unable to establish a functioning radio command net (during peace-time, the Red Army tried to avoid use of radio communications in order to limit opportunities for adversary signals intercepts, but when war erupted suddenly, most units had neither the experience nor the correct code books to initiate secure communications) so he was forced to rely upon civilian phones to try and coordinate his forces. In this command vacuum, local commanders began making their own decisions on how to respond to the German invasion. The Soviet 5th Army, headquartered in Lutsk, directed General-major Semen M. Kondrusev’s 22nd Mechanized Corps to counterattack the German forces threatening Vladimir Volynskii. Although most of this corps was about 100km from the border, by chance its most powerful formation, Polkovnik Petr Pavlov’s 41st Tank Division, was conducting field training just north of Vladimir Volynskii. Pavlov had thirty-one KV-2 heavy tanks (which lacked 152mm ammunition) and 342 T-26 tanks, which were in an excellent position to counterattack the German 14.Panzer-Division as it marched over the bridge at Ustilug. Instead, Pavlov found himself in a quandary that was not uncommon in the Red Army of June 1941 – he was out of radio communications with Kondrusev’s corps headquarters and his pre-war mobilization orders directed him to deploy to Kovel – away from the Germans at Ustilug. Pressured by local Soviet commanders to do something to help the crumbling border defenses, Pavlov split the difference by sending the bulk of his tanks on the road to Kovel, but detaching a tank battalion under Major Aleksandr S. Suin with fifty T-26 light tanks to support Soviet infantry at Vladimir Volynskii. Suin’s battalion arrived just in time to be shot to pieces by German panzerjäger, who knocked out thirty of his T-26 tanks and forced him to abandon Vladimir Volynskii.
Only vaguely aware of the extent of German advances by the end of 22 June, Kirponos was able to get in touch with General-major Ignatii I. Karpezo’s 15th Mechanized Corps, located near Brody, and order them to counterattack Crüwell’s 11.Panzer-Division near Radekhov while the rest of Kondrusev’s 22nd Mechanized Corps deployed to counterattack at Vladimir Volynskii. The 1st Anti-tank Brigade (RVGK) under General-major Kirill S. Moskalenko, which was fully motorized and equipped with forty-eight 76.2mm F-22 anti-tank guns and seventy-two 85mm M1939 anti-aircraft guns, was ordered to create a blocking position west of Lutsk. Moskalenko’s anti-tank unit was one of the most powerful anti-armour formations in the Southwest Front and was also plentifully supplied with anti-tank mines. Kirponos had four other first-echelon mechanized corps in the Southwest Front, but the 4th and 8th Mechanized Corps spent the first few days of the war marching and counter-marching to no useful purpose. Rokossovsky’s cadre-strength 9th Mechanized Corps was beginning a 200km march to Lutsk, but would not arrive for a few days. The 16th Mechanized Corps was even further away from the border. In short, although Kirponos had an overall 6–1 numerical superiority in tanks over von Kleist’s Panzergruppe 1, the piecemeal arrival of Soviet armour on the battlefield meant that the Red Army’s advantage was whittled down to a 2–1 local superiority, which was adequate for defense but not attack. Nevertheless, an order from the Stavka, signed by Georgy Zhukov, was received at Kirponos’ command post at 2300 hours on 22 June, directing Kirponos to counterattack with five mechanized corps within less than forty-eight hours.
On 23 June, von Kleist’s armour advanced eastward, with Kühn’s spearhead in the north and Crüwell’s spearhead in the south. They were advancing along very narrow frontages and not mutually supporting, as they were separated by a distance of over 50km. Under these circumstances, the Red Army should have been able to inflict heavy losses on these vanguard units. During the morning, the 13.Panzer-Division reinforced the 14.Panzer-Division across the Western Bug and, together with infantry from 6.Armee, they began to mop up the remaining Soviet border defenses. Crüwell’s 11.Panzer-Division advanced to Radekhov with Kampfgruppe Riebel (Oberstleutnant Gustav-Adolf Riebel’s Panzer-Regiment 15 and the Luftwaffe I/Flak Regiment General Göring, with twelve 8.8cm flak guns) and Kampfgruppe Angern (Oberst Günther von Angern’s 11 Schutzen Brigade and the 119.Artillerie-Regiment). Part of the Soviet 20th Tank Regiment, from General-major Sergei I. Ogurtsov’s 10th Tank Division, was in the town, but they were apparently caught by surprise and hurriedly abandoned Radekhov, along with twenty BT-7 and six T-34 tanks. After securing the town, Riebel sent a tank platoon from Oberleutnant Edel Zachariae-Lingenthal’s 5./Panzer-Regiment 15 forward to reconnoiter to the south and this platoon spotted a group of Soviet tanks in column approaching Radekhov from the southwest along a road. The German tanks quickly occupied hull-down ambush positions and waited until the Soviets – which were T-34 medium tanks – were within 100 meters. Then the five Pz.IIIs opened fire with 3.7cm and 5cm Panzergranate AP rounds.
Even though at this short distance every shot was a hit, the Russians drove on without much visible effect … Despite repeated hits, our fire had no effect. It appears as if shells are simply bouncing off. The enemy tanks disengaged without fighting and retreated.
This Soviet probe merely alerted Riebel to the presence of an impending Soviet armoured counterattack and he promptly deployed the I and II/Panzer-Regiment 15 in a linear defense just west of Radekhov, with the Luftwaffe 8.8cm flak guns in the center and Kampfgruppe Angern’s artillery behind him.21 Soon thereafter, Ogurtsov conducted a sloppy, unsupported attack with just two tank and two motorized infantry battalions across open terrain in broad daylight. He refused to wait for reconnaissance to spot the German positions or his own artillery to deploy, so his forces went into battle blind. Tank–infantry cooperation was virtually non-existent. The 100-odd Soviet tanks attacked in several waves; first the light BT-7 and BA-10/20 armoured cars, then the medium T-28 and T-34 and finally the KV-1 heavy tanks. The German tankers opened fire at about 400 meters and easily put paid to the first wave of Soviet light tanks, but the T-34s began engaging the German tanks from 800–1,000 meters and knocked out three Pz.III and two Pz.IV tanks. The 5cm KwK 39 L/42 was completely ineffective at that range, but in desperation Oberleutnant Zachariae-Lingenthal ordered his Pz.IVs to fire 7.5cm Sprenggranate 34 (HE) rounds at the T-34s. Since the T-34s had been committed straight after a long approach march, they were still carrying reserve fuel drums on their back decks, which could be set alight by shell fragments. A lucky hit or two convinced the Soviets to pull back. Despite the near invulnerability of their armour to German 3.7cm and 5cm guns, a number of T-34s and KV-1s were immobilized by hits on their tracks and then abandoned by their crews. After suffering nearly 50 per cent losses, Ogurtsov broke off his amateurish attack. The Soviet 10th Tank Division lost forty-six tanks in their first battle with 11.Panzer-Division, but knocked out five German tanks and several anti-tank guns. After the action, Zachariae-Lingenthal inspected some of the abandoned T-34 tanks, alarmed by its superior firepower and armoured protection and later wrote, ‘this was a shocking recognition to the German panzer and panzerjäger units and our knees were weak for a time.’
Meanwhile, Kirponos tried vainly to bring up more of his mechanized corps in order to comply with the Stavka-directed counteroffensive on the morning of 24 June, but only the 15th and 22nd Mechanized Corps were in any position to do anything. Von Kleist was gradually feeding more armour into the battle as the Soviet border defenses were eliminated, but he initially held back the 9.Panzer-Division and his four motorized infantry divisions. This was an important command decision – throughout the Battle of Dubno, the Germans maintained strong mobile reserves, while Kirponos committed each formation as it arrived with nothing left in reserve to deal with enemy breakthroughs. Due to poor Soviet radio security at the division level and below, the German 3rd Radio Intercept Company was able to detect Soviet armour units moving toward the border. Although army and higher-level units used good encryption on their radio nets, the tank regiments and divisions employed simpler ciphers that the Germans could break and often failed to change frequencies and call signs for days after compromise. Soviet tank units also had a bad habit of calling for fuel supplies just before launching an attack, which provided German intelligence officers with a valuable indicator. Thus poor Soviet radio procedures in tank units handed another advantage to the German panzer divisions.
Not surprisingly, no grand Soviet counteroffensive materialized on the morning of 24 June, since neither the 15th nor 22nd Mechanized Corps were ready to attack. Instead, Kühn’s 14.Panzer-Division attacked eastward toward Lutsk at 0800 hours, supported by bombers from Fliegerkorps V. Kühn’s panzers brusquely pushed aside a Soviet rifle division blocking the road to Lutsk, but then ran straight into Moskalenko’s 1st Anti-tank Brigade west of Lutsk. Moskalenko’s unit was caught with its guns still limbered in column, enabling the panzers to shoot up his lead battalion, but once the rest of his unit deployed on line, the German tanks were vulnerable in the open. The Soviet anti-tank gunners were easily capable of penetrating the Pz.III and Pz.IV tanks at 1,000 meters or more, and it was only the lack of supporting infantry or tanks that prevented Moskalenko from giving 14.Panzer-Division a very bloody nose. As it was, both sides suffered significant losses in this first major duel between panzers and Soviet anti-tank guns. It was not until 1400 hours that the 22nd Mechanized Corps was finally ready to attack, and then only with part of the 19th Tank Division. Bravely charging, a battalion of forty-five T-26 light tanks struck the left flank of the 14.Panzer-Division near Voinitsa and briefly regained some ground. However, the Germans were merely withdrawing to regroup and at 1800 hours they struck back with a combined-arms attack that shattered the 19th Tank Division. Not only were most of the division’s light tanks lost, but the division commander was wounded and all three regimental commanders were killed or captured, as well as the artillery commander. The remnants of the Soviet division fell back in disorder toward Lutsk, along with Moskalenko’s anti-tank brigade. During the retreat, Kondrusev was killed by German artillery fire, leaving the 22nd Mechanized Corps leaderless.
Nor had Karpezo’s 15th Mechanized Corps been able to stop Crüwell’s 11.Panzer-Division, which bypassed Soviet blocking positions east of Radekhov and advanced 55km to the outskirts of Dubno. Karpezo seemed to think that his mission was to defend Brody, and was content to sit almost immobile as Crüwell’s division marched past him. Indeed, Crüwell took considerable liberty with Karpezo, leaving his right flank dangerously exposed – but nothing happened. German panzer commanders were trained to accept risk and ignore their flanks, and in 1941 this often paid handsome dividends. Generaloberst Hans-Valentin Hube’s 16.Panzer-Division followed in Crüwell’s path, as well as two infantry divisions, to exploit the breakthrough. Zhukov, who had arrived as Stavka representative at Kirponos’ command post at Tarnopol, ordered him to launch a counteroffensive into the flank of 11.Panzer-Division by 0700 hours on 25 June, even though this would be another piecemeal attack. While the German panzer corps commanders used radio to direct and maneuver their panzer-divisions in coordinated fashion, the Soviet mechanized corps operated with little or no coordination with other friendly formations at this point. Lack of C2-driven coordination prevented Kirponos from effectively massing his armour on the battlefield.
While the main armoured battle was developing around Dubno, Kirponos’ strongest armoured formation – General-major Andrey Vlasov’s 4th Mechanized Corps – was senselessly committed by the 6th Army commander to local counterattacks against the German 17.Armee approaching L’vov. Vlasov’s counterattack did not go well, as his armour was also committed piecemeal and without artillery support. Polkovnik Petr S. Fotchenkov’s 8th Tank Division lost nineteen of its 140 T-34s and the 32nd Tank Division lost sixteen tanks on 24–25 June fighting German infantry units. Vlasov did not report these heavy losses to Kirponos, but did claim the destruction of thirty-seven enemy tanks, even though no German armour was in this sector. Even worse, the tanks of the 4th Mechanized Corps were marched hither and yon by the 6th Army, which wanted tanks everywhere at once, but the result was that hundreds of tanks fell out due to mechanical defects.
25 June was a very good day for Panzergruppe 1. Generaloberst Eberhard von Mackensen had both 13 and 14.Panzer-Divisionen advancing toward Lutsk, and together they were strong enough to force Moskalenko’s anti-tank brigade to withdraw. By the afternoon, German tanks from 13.Panzer-Division seized a bridgehead over the Styr River and occupied Lutsk. The Soviet 9th and 19th Mechanized Corps, approaching from the east, were too late to save the city. Karpezo continued to sit immobile, ignoring Zhukov’s attack order, and allowed Crüwell’s 11.Panzer-Division to fight its way into Dubno by 1400 hours. Soviet infantry attempted to form a defensive line behind the Ik’va River, but Crüwell’s fast-moving kampfgruppen defeated this effort. The easy capture of both Lutsk and Dubno effectively drove a wedge between the Soviet 5th and 6th Armies, making efforts to coordinate joint actions even more difficult. The only positive aspect of the day for the Soviets was that the 9th and 19th Mechanized Corps were assembling near Rovno and the 8th Mechanized Corps had arrived to reinforce Karpezo at Brody. On a map, it appeared to Zhukov that the Red Army could mount a powerful armoured pincer counterattack to cut off the vanguard of Panzergruppe 1 at Dubno.
However, Zhukov’s efforts to jump-start a counteroffensive were no more successful on 26 June and only resulted in further diminishing Kirponos’ armour. General-major Konstantin K. Rokossovsky established a fairly strong blocking position due east of Lutsk, which prevented either the 13 or 14.Panzer-Divisionen from advancing directly on Rovno, but recognizing that his 100-odd light tanks stood no chance against Mackensen’s III Armeekorps (mot.), he opted to make only a demonstration to comply with the letter of Zhukov’s order and then shifted to the defense. General-major Nikolai V. Feklenko was less circumspect and obediently launched an attack with his 19th Mechanized Corps against 11.Panzer-Division at Dubno around 1400 hours. Feklenko attacked with about 200 tanks, but only two KV-1 and two T-34; the rest were either T-26 or T-37 scout tanks armed only with machine-guns. Crüwell easily repulsed Feklenko’s counterattack and both KV-1 tanks were lost. Adding insult to injury, Crüwell boldly pushed his motorcycle battalion, Kradschützen-Bataillon 61, 30km eastward to the outskirts of Ostrog.