The city was besieged as part of the Lower Silesian Offensive Operation (8–24 February 1945) on 13 February by the 6th Army of the 1st Ukrainian Front commanded by Marshal Ivan Koniev, and the encirclement of Breslau was completed the following day. The 1st Ukrainian Front forces besieged the city with the 22nd and 74th Rifle Corps, and the 77th Fortified Region, as well as other smaller units. Even approximate estimates vary greatly concerning the number of German troops trapped in Breslau. Some sources claim that there were as many as 150,000 defenders, some 80,000 and some 50,000. The Siege of Breslau consisted of destructive house-to-house street fighting. The city was bombarded to ruin by artillery of the Soviet 6th Army, as well as the Soviet 2nd Air Army and the Soviet 18th Air Army. During the siege, both sides resorted to setting entire districts of the city on fire.
On 15 February, the German Luftwaffe started an airlift to aid the besieged garrison. For 76 days, until 1 May, the Luftwaffe made more than 2000 sorties with supplies and food. More than 1,638 short tons (1,486 t) of supplies were delivered.
On 22 February, the 6th Army occupied three suburbs of Breslau, and during the next day, the 6th Army troops were in the southern precincts of the city itself.
By 31 March, there was heavy artillery fire into the north, south, and west of Breslau suburbs. The 6th Army witnesses noted that much of the city was in flames.
On 20 April, where possible, General Niehoff had chocolates distributed to the troops in honor of Hitler’s 56th birthday.
On 4 May, the clergy of Breslau — Pastor Hornig, Dr. Konrad, Bishop Ferche, and Canon Kramer — demanded that Niehoff surrender the town. Niehoff dismissed the clergy without a definitive answer. In the afternoon of the same day, Pastor Hornig repeated his demand in an address to the troop commanders. Hanke ordered Niehoff not to have any further dealings with the clergy.