On July 23, Sixth Army began a pincer operation with its XIV and XXIV Panzer Corps against 62nd Army. By the end of the next day two rifle divisions of the army had been pushed aside to the north, the army's right flank had been deeply penetrated and partly encircled in the Maiorovsky region before the advance had to be slowed due to supply difficulties and Soviet resistance. Stalin ordered the half-formed tank armies into the attack against the northern pincer, which began on the 25th. While these attacks were too disjointed to achieve decisive results, by the next day German progress was halted, with Soviet tanks breaking into the rear of XIV Corps, and a 35 km gap remaining between the pincers. The rebuilding 21st Army joined the counterstroke that day as well.