Lvov–Sandomierz Offensive
The First Army entered Poland from Soviet territory in the summer of 1944, on the right wing of the Lvov–Sandomierz Offensive, fighting in the battles during the Soviet crossing of the Vistula River around Dęblin and Puławy. In September 1944, units of the First Army were involved in heavy fighting during the latter stages of the Warsaw Uprising, after crossing the Vistula following the capture of Warsaw's eastern Praga district, but suffered heavy losses.