On January 14th, Rokossovskiy's 2nd Byelorussian Front attacked north and nortwest from the Narew bridgehead. The aim was to reach the debouch of Weischel and Danzig. On the 20th Stavka suddenly ordered Rokossovskiy to change the attack in a notheasterly direction into the center of East Prussia. On the right flank, the 3rd Guards Cavalry Corps advanced quickly and took Allenstein at 0300 in the morning of the 23rd. On the left flank, Volskii's 5th Guards Tank Army advanced towards the city of Elbing. Parts of the lead Tank Brigade headed into the city on January 23rd after being mistaken for German tanks. A violent and chaotic engagement arose in the streets of the old city. On the 28th the attack renewed.