The heaviest battles fought by the Poles included the breaching of the Pomeranian Wall, accomplished by the badly battered First Polish Army and the Soviets on 5 February, during their East Pomeranian Offensive. The Poles, commanded by General Stanisław Popławski, then led the assault on Kolberg, completed on 18 March. Gdynia and Danzig were taken over by the 2nd Belorussian Front by the end of March, with the participation of the Polish 1st Armoured Brigade. The First Polish Army's campaign continued as it forced the Oder in April and finally reached the Elbe River in early May.