Army Group South of field-marshal Gerd von Rundstedt, to which the Romanian forces were subordinated, was split in two by the Pripyat Marshes. Its main effort at the beginning of Operation Barbarossa had to be concentrated in the northern sector, while the forces in Romania had to wait for the offensive to penetrate deeper into the Ukraine in order to start the attack. This decision was taken by the OKH in the spring of 1941, because gen. Franz Halder considered the Prut River to be a serious barrier for a motorized assault and because the offensive potential of the Romanian troops wasn't considered appropriate by the German planners. That is why the vast majority of the German mechanized forces of Army Group South was concentrated in Poland, while on the Romanian front there were only the Romanian motorized units. As it was to be seen, the Prut River was not such a formidable barrier in the conditions of a surprise attack. The Romanian soldiers occupied several intact bridges from the early hours of the war. Probably a powerful offensive from the first day on the front in Moldavia would have caused serious problems to the Soviet Southwestern Front, which put up a powerful resistance to von Rundstedt's troops.

The forces that will take part in the operations in Bessarabia and Northern Bukovina were: the Romanian 3rd Army (the Mountain and Cavalry Corps) in the north, commanded by lt. gen. Petre Dumitrescu, in the center the German 11th Army of gen. Eugen von Schöbert (the German 11th, 30th and 54th Corps), and in the south, the Romanian 4th Army (the 5th, 3rd and 11th Corps) of lt. gen. Nicolae Ciuperca. In the Danube Delta was deployed the Romanian 2nd Corps, commanded by maj. gen. Nicolae Macici. All these formed the Antonescu Army Group. On 22 June 1941 the total number of Romanian soldiers in the first line was 325,685, distributed in 12 infantry divisions, one armored division, one reserve infantry division, one frontier-guard division, 3 cavalry brigades, 3 mountain brigades and 2 fortification brigades. The Wehrmacht had 5 infantry divisions on the Prut River.

The offensive power of the ARR (Aeronautica Regala Romana=Romanian Royal Aeronautics) was concentrated in the Combat Air Grouping (Gruparea Aeriana de Lupta), which had a total of 253 aircraft, out of which only 205 were available for action on 22 June. Their mission was to gain air supremacy over Bessarabia and Northern Bukovina and then support the offensive of the Romanian 4th Army. It was made up of 4 bomber groups (the 1st, 2nd, 4th and 5th) and 2 independent bomber squadrons (the 82nd and 18th), 3 fighter groups (the 5th, 7th and 8th), 4 observation squadrons (the 11th, 12th, 13th and 14th) and one long range recon squadron (the 1st).

The 3rd and 4th Army had their own observation, light bomber and liaison squadrons: the 3rd had 5 squadrons assigned to it and the 4th had 4 squadrons. One observation squadron (the 15th) was attached to the 1st Armored Division.

Behind the front line, the territory of Romania was divided between the 2nd Air Region: 2 fighter groups (the 3rd and 4th) and one liaison squadron (the 112th) and the 3rd Air Region: the 6th Fighter Group and one liaison squadron (the 113th). In Dobruja were stationed 2 seaplane squadrons (the 101st and 102nd), one observation squadron (the 16th) and one fighter squadron (the 53rd). ARR fielded 672 airplanes at the beginning of Operation Barbarossa, while the Luftwaffe forces in Romania totaled 420 aircraft.

The Danube and the Black Sea coast were defended by the Danube Division (15 military and 30 auxiliary ships) and by the Sea Division of the Navy (14 military and 9 auxiliary ships, 20 seaplanes). The Marine Regiment (3 battalions) was stationed in the Danube Delta.

On the other side of the front in Northern Bukovina was the Soviet 12th Army, commanded by lt. gen. P. G. Ponedelin, which was subordinated to the Southwestern Front. In Bessarabia was the Soviet 9th Army of gen. T. Cherevichenko, which was reinforced later with the 18th Army from the Moscow Military District. The mobile forces were concentrated in the 2nd (11th and 16th Tank Divisions, 15th Motorized Division and 6th Motorcycle Regiment) and 18th Mechanized Corps (44th and 47th Tank Divisions, 218th Motorized Division and 26th Motorcycle Regiment). On 25 June, these two armies formed the Southern Front under the command of gen. I. V. Tiulenev. It had 16 divisions deployed in depth in two lines: 5 rifle, 2 mountain rifle and one cavalry division on the border and one rifle and one cavalry division and the two mechanized corps between the Prut and Dnister Rivers. The reserve was made up of 3 rifle divisions and one AT brigade. There were also the troops of 5 fortified regions (80th, 81st, 82nd, 84th and 86th). In total they amounted to 364,700 soldiers. The Soviet Black Sea Fleet (ChF) was much more numerous than the Romanian one and the VVS had 1,750 airplanes in the area.

Sunday, 22 June 1941. At 0300 hours, the first German and Romanian reconnaissance aircraft passed the Prut River and at 0315 hours the bombers were taking off from airfields in Moldavia, heading for Soviet airbases in Bessarabia, while the artillery had commenced pounding Red Army positions. The first line troops executed several incursions in the enemy lines.

In the north, the 3rd Army was reduced only to the Mountain Corps (the 1st, 2nd and 4th Mountain Brigades, 8th Cavalry Brigade and 7th Infantry Division), because the Cavalry Corps had been subordinated directly to the German 11th Army. In fact the 3rd Army command did not have any operative attributes until 2 July 1941, when the ground offensive started also in the Romanian sector. Early in the morning, the 7th Infantry Division occupied the Bahrinesti village and the recon raids of the 1st and 4th Mountain Brigades were repulsed. The 2nd Calarasi Regiment General David Praporgescu from the 8th Cavalry Brigade temporarily captured the Fantana Alba village. It was lost following a Soviet counterattack. In the Cavalry Corps sector, the 3rd Squadron/6th Rosiori Regiment from the 5th Cavalry Brigade took the pillboxes on the Bobeica Hill, north of Dorohoi. During the attack, 2nd lt. Paul Liviu Popescu was killed, who later received the Mihai Viteazul Order 3rd class posthumously, being probably the first Romanian officer to earn this high distinction during WWII. The 6th Infantry Division made a bridgehead at Mitoc, but had to abandon it during the evening following a counterattack.

On the front of the 4th Army, the Guard Division created two bridgeheads over the Prut River with the 6th Guard Infantry Regiment Mihai Viteazul in the Falciu and Bogdanesti areas. From the 3rd Battalion/11th Infantry Regiment from the 21st Infantry Division, two rifle companies and two machine-gun platoons, under the command of maj. Ciprian Ursuleac, occupied the bridge over the Prut at Oancea. Another bridge was captured intact at Giurgiulesti, but was later abandoned.

During the first day of the war, the Romanian bombers claimed 100 aircraf tdestroyed on the ground, but aerial photographs only confirmed 37 of them. To these another 5 claims by machine-gunners onboard can be added. In total, nine bombers were lost that day. The fighters had 10 confirmed kills, without any irreparable loss of their own. Also four recon aircraft were lost and several others were damaged. It was one of the hardest days for ARR during the campaign in the USSR.

The Soviet land and naval artillery replied and bombarded the Romanian shore. On the Danube, one monitor and one armored patrol boat tried to attack Tulcea, but were repulsed by the NMS Basarabia and NMS Mihail Kogalniceanu monitors, which destroyed the patrol boat.

The Soviet long range bomber force started to carry out raids over Romanian territory, but because they lacked escorts, they suffered terrible losses. On 23 June 1st lt. Horia Agarici from the 53rd Fighter Squadron entered a formation of five Soviet bombers with his Hawker Hurricane Mk. I and shot down three SBs near Constanta.

The same day, the second of the war for the Romanian Army, the 7th Infantry Division and the 8th Cavalry Brigade resumed their local attacks and captured the Cerepcauti and Fantana Alba villages.

In the sector of the German 11th Army, to which the Romanian 8th Infantry Division was subordinated, the 7th Vanatori Regiment tried to make another incursion during the night, but without success. The 8th Vanatori Regiment, from the same division, repulsed the Soviet infantry that attempted to cross the river lighted with searchlights. The 14th Infantry Division participated with one battalion, together with the German 198th Infantry Division, at the establishing of a bridgehead at Sculeni, north of Iasi.

During the night, at 0130-0200 hours, the men of the 6th Guard Infantry Regiment in the positions east of the Prut were attacked by the Soviet 5th cavalry Division, but held out. The 9th Company made a bayonet charge and pushed back the enemy and captured 4 LMGs and 13 rifles. At about 1900 hours another assault took place, but was also repulsed. The regiment lost that day 24 killed, 24 wounded and 8 missing. The 1/2nd Guard Vanatori Regiment made an incursion on the Ranzesti-Gheltosul direction (south of Tiganca) with a group under the command of 1st lt. Constantin Petrescu. He managed infiltrate through the lines and occupy a hill north of Gheltosul, which he held until evening, when the detachment returned to the Romanian lines.

To the south, on the Danube, the Tulcea Tactical Group (the NMS Basarabia and NMS Mihail Kogalniceanu monitors and 4 patrol boats) had another clash with the Soviet fleet, damaging two monitors, two armored patrol boats and a tug. Downriver from Reni, the Romanian monitors bombarded Soviet artillery positions and damaged another monitor and sunk one armored patrol boat and one barge.

On 24 June the incursions and artillery duels continued on the entire front of Army Group General Antonescu. The Soviet infantry attacked with armor and air support the bridgeheads at Badarai and Sculeni, where troops from the 8th Infantry Division and of the German 198th Infantry Division were located. At Bogdanesti, the 3rd Battalion/6th Guard Infantry Regiment was heavily bombarded by both artillery and aircraft and faced several infantry assaults, but managed to keep its positions. It had 5 killed and 4 wounded. To the south, the other unit of the 5th Corps, the 21 Infantry Division , used the bridge at Oancea to make several incursions, which went as far as Cahul (1st lt. V. Lizac Detachment from the 1st Battalion/24th Infantry Regiment). The bridge was however destroyed by Soviet artillery behind them. The same fate had the bridge at Falciu.

On the Chilia arm of the Danube, Soviet troops occupied Pardina, but were repulsed by the Tulcea Tactical Group and the artillery of the 10th Infantry Division.

The most important naval engagement in the Black Sea in 1941 took place on 26 June. A Soviet naval group led by the Voroshilov cruiser, accompanied by six destroyers and several other ships tried to execute an attack on the Constanta port facilities. The group had been spotted 60 miles east of the coast at 0030 by the NMS Delfinul submarine, which was on patrol in the area. Thus the defence had some time to prepare. A much stronger task force, with the Pariskaya Komuna battleship was waiting 120-150 miles off the coast, prepared to exploit an eventual success of the initial force.

The Voroshilov group sent two flotilla leaders (the Moskva and the Kharkov) in a scouting raid on the Constanta harbor. At 0358 hours, the two ships opened fire with their 130 mm guns from 15 miles. In a relatively short time (ten minutes) they fired 350 rounds on the Palas railway station and on the port, managing to set on fire a munitions train and some oil tanks.

The destroyers NMS Regina Maria and NMS Marasti, which were near the Tuzla Cape maneuvered to a parallel direction and opened fire at 0412 from 14 miles with their 120 mm artillery pieces. Because of the high profile of the coast around Tuzla, the Romanian destroyers were difficult to spot, in opposition with the Soviet ships, which were clearly silhouetted against the dawn. At 0420 the Kharkov was hit. The German coastal batteries joined the duel. The 280 mm Tirpitz battery fired at 0422, but after five salvoes the two ships sailed out of its range. The Moskva had also been damaged by the Romanian destroyers. Its main mast shot off by a small caliber round, most likely a 120 mm shell. In total they had fired only 12 salvoes.

As they were retreating, the damaged Moskva entered a minefield, hit one, broke in two and sank very quickly. Only 69 of its 400 men crew survived.

Two Romanian motor torpedo boats, the NMS Viforul and the NMS Vijelia, attempted to attack the Kharkov, but they were driven off by the rest of the Voroshilov’s group. In the meantime, one of its escorts set off a mine, which damaged the cruiser.

Also, a formation of Soviet bombers from 40 BAP/ChF attacked the port facilities, but it did not manage to cause too much damage. The NMS Murgescu claimed two shot down and the NMS Marasti claimed one. They lost in total nine SBs.

In the Danube Delta, at 0300 hours, a powerful artillery preparation began in the positions of the Romanian marines in the Chilia Veche and Periprava sectors. Soviet units loaded on 8 armored patrol boats landed north of Chilia Veche, where the 15th Marine Battalion was located, while two armored patrol boats and two troops transports infiltrated on the Tataru arm and disembarked the troops behind the Chilia Veche positions. A part of the Romanian soldiers retreated to the Casla grind, but the majority were captured. The 15th Battalion lost 358 men (11 officers, 13 NCOs and 334 soldiers). The lack of AT guns that could have knocked out the armored patrol boats and the poor quality of the officers and men in the unit, led by lt. col. Ioan Albescu, led to this disaster. At Periprava, however, the 17th Marine Battalion had several 47 mm Schneider model 1936 AT guns. Four Soviet armored patrol boats were knocked out and the attack was repulsed.

The following day the fighting continued in the bridgeheads over the Prut. The 2nd Battalion/6th Vanatori Regiment repulsed an assault at Sculeni, while at Bogdanesti the Guard Division made several incursions in the enemy positions loosing 83 men (9 killed, 11 wounded and 63 missing). Such local clashes, followed by artillery duels and air bombardments were characteristic for the 22-30 June 1941 period on the front of Army Group Antonescu. The Romanian casualties rose up to 1,475 (442 killed, 659 wounded and 374 missing).