The 'Danzig Offensive Operation' was the second of the four sub-operations which in total constituted the Soviet 'East Pomeranian Strategic Offensive Operation', and its primary objective was the seizure of the port city of Danzig (Gdansk in Polish) from General Martin Gareis’s XLVI Panzerkorps of General Dietrich von Saucken’s 2nd Army within Generaloberst Gotthard Heinrici’s Heeresgruppe 'Weichsel' (25/31 March 1945).
The Soviet offensive was controlled by Marshal Sovetskogo Soyuza Konstantin K. Rokossovsky’s 2nd Belorussian Front, and the four major formations committed to the offensive were General Polkovnik Ivan I. Fedyuninsky’s 2nd Shock Army, General Polkovnik Pavel I. Batov’s 65th Army, General Polkovnik Ivan T. Grishin’s 49th Army and General Leytenant Vladimir Z. Romanovsky’s 19th Army.
It was on 25 March that the Soviet forces began their assault on Danzig, which was held by some 24,500 men supported by 200 armoured fighting vehicles and 500 pieces of artillery against the attack of 95,500 men of the Soviet army supported by 750 armoured fighting vehicles and 2,500 pieces of artillery. A feature of the assault was that parts of Soviet troops entered the city from the west after the city had been bypassed by the main forces of the 'East Pomeranian Strategic Offensive Operation'. The German defence thus faced assault from the west and south as well as from the east. It as in the east that the Germans had expected to have to defend the city, if at all, and where they had therefore built the majority of their fortified strongpoints.
On the night of 26/27 March, Soviet troops entered Emaus, Danzig’s western suburb, and by 08.00 on 27 March, battalions of the 59th Guards Tank Brigade , reinforced by ISU-122 self-propelled guns of the the 2 and 3/60th Guards Tank Brigade, machine gunners of the 28th Guards Motorised Brigade and sappers of the 125th Guards Engineer Battalion, reached the Franciscan church in Emaus. The streets of the city were blocked by anti-tank ditches and mined barricades. Some buildings were also mined so that their demolition would block the routes by which the tanks of the Soviet assault groups might most readily continues their advances. German PzKpfw V Panther battle tanks also operated along the streets of Emaus .
On 27 March, units of the 59th and 60th Guards Tank Brigades were moving along the Carthausstrasse and Oberstrasse streets, and managed to advance to the Neugarten area. The Soviet advance was greatly aided by the efforts of the Soviet tactical air forces providing support with bombs and the fire of cannon and machine guns, which also inflicted severe damage on targets in the port and the city in day and night attacks. By 15.00, the central part of the Schidlitz suburb had been taken. On the same day, the city’s German defence began to disintegrate. Generalleutnant Clemens Betzel, commander of the 4th Panzerdivision, was killed in the Oliwa Gate area in an area bombardment by 'Katyusha' multiple-launch rocket systems; Betzel was a succeeded in command of the division by Oberst Ernst-Wilhelm Hoffman. According to German sources, for the lack of any communication capability with higher command elements, the 4th Panzerdivision promptly assumed command of all the German units still holding the defences among the ruins of the city, in which at that time German communications were limited to the short-wave equipment of tanks. During the night of 27/28 March, the German garrison began to withdraw from the old part of Danzig, through Wyspa Spichrzów (granary island) and the area behind the Neue Mottlau (Motława) canal, leaving stay-behind parties with some artillery crews and anti-aircraft guns, of which the last were now operating in the direct-fire role. The order to withdraw behind the canal did not reach all units. Part of the garrison was either destroyed in powerful artillery strikes or chose to surrender. The latter was the option selected by the garrisons of the forts on the Bischofsberg and Hagelsberg heights.
By 09.00 on 28 March, the Neugarten area had been cleared by the Soviet advance, by 12.00 the central part of Danzig had been taken, and by 14.00 Soviet infantry units, supported by armour, had consolidated positions on Ambarny island. The Mattenbuden bridge was blown up, and during the night of 29/30 March a German counterattack on the Milhkannen bridge was repulsed by a reinforced platoon of the 1st Assault Engineer Brigade. The armour of the VIII Guards Tank Corps did not advance in the afternoon of 28 March for lack of crossings over the Motlawa. In the northern part of Granary island, the Neue-Mottlau canal was successfully crossed by Soviet infantry units, which then became involved in the fighting for the Danzig’s 86th and 87th quarters on the eastern bank of the Neue-Mottlau canal.
On the night of 29/30 March German infantrymen, with armoured support, launched several counterattacks from the Breitenbach Gasse area in an effort to dislodge Soviet infantry units from their positions in the 86th quarter and drive them into the canal. While the Germans had some success, they failed to drive the Soviets from the houses along the canal’s bank.
On 29 March, the self-propelled guns of the 60th Guards Tank Brigade and tanks of the 3rd Battalion of the 59th Guards Tank Brigade finally cleared Granary island from scattered groups of German machine gunners. During the morning of the same day, motorised infantry crossed the Milhkannen bridge and pressed the Soviet advance into the Lower Town of Danzig’s eastern part. An attempt by tanks to cross the Neue-Mottlau canal was unsuccessful: only two machines of the 59th Guards Tank Brigade managed to cross the Milhkannen Bridge. The tanks that had succeeded in crossing were sited in the customs administration building in the lower city. Heavy fire from the area of the barracks, the gymnasium and the church of St Barbara rendered impossible any further attempts to cross. Throughout the first half of 29 March, tanks and self-propelled guns of the VIII Guards Tank Corps (59th and 60th Guards Tank Brigades) were supported by the fire of the infantry of the 28th Guards Motorised Brigade and other troops in the 86th and 87the quarters.
By 12.00 on 29 March, in the area of the demolished Mattenbuden bridge, a tank crossing point had been established across Novaya Motlawa. Tanks of the 59th Guards Tank Brigade crossed and, with the support of a battery of five self-propelled guns of the 60th Guards Tank Brigade, moved along the Reitergasse and Weidengasse street. By 14.00, the tanks had broken the resistance of the remnants of the Danzig garrison, and advanced to the St Barbara church, where a small armoured battle began. During the night of 30/31 March, elements of the 59th and 60th Guards Tank Brigades, the 28th Guards Motorised Brigade and other units finally cleared the area of the eastern part of Danzig’s lower city. On 31 March, Soviet forces cleared the suburbs of Kneipab and Strodeich, and the Germans had been driven back behind the Mertvaya Visla waterway in Hoybud.
The 'Danzig Offensive Operation' ended on 31 March with the Soviet forces in complete control of the city. In the operation the Soviets had lost 10,000 men, 80 armoured fighting vehicles and 800 pieces of artillery and mortars, while the Germans had lost 22,000 men including 3,000 men taken prisoner, 195 armoured fighting vehicles and 450 pieces of artillery. With Danzig fall, the Germans retreated farther to the west as the Soviets pressed their advance. Marshal Sovetskogo Soyuza Georgi K. Zhukov’s 1st Belorussian Front, which had closed on Berlin, was now reinforced with formations of the 2nd Belorussian Front.