Konev's 1st Ukrainian Front opened the Prague Offensive with an attack by the 3rd and 4th Guard Tank Armies and the 13th, 3rd Guards, and 5th Guards combined-arms armies. This group of five armies was Konev's main attack and pushed south from the area around Riesa. Facing Konev's thrust were troops of the German 4th Panzer Army. The attack opened with a reconnaissance-in-force in the morning, followed by a brief but powerful artillery barrage. 13th, 3rd Guards, and both tank armies (as well as two other tank corps) attacked southward in the afternoon, with the 13th Army and the 4th Guards Tank Army pushing forward some 23 kilometers. By evening, 5th Guards Army had joined the attack with the objective of capturing Dresden.