Corps and the 24th Tank Corps, defending in the area from Izyaslav to Ilintsy, were transferred from the 4th to the 1st Panzer Army, as a result of which the front of the 4th Panzer Army was significantly reduced. But more important was the transfer of 5 panzer divisions (1st, 6th, 16th, 17th Panzer Divisions, 1st SS Panzer Division Leibstandarte SS Adolf Hitler) from the Uman direction to the area south of Yampol, Starokostiantyniv, the 7th Panzer Division from Dubno, the 357th and 359th Infantry Divisions from the reserve of the OKH in Germany and the 68th Infantry Division from Poland after refitting (badly damaged during the Zhitomir–Berdichev offensive). The Soviet intelligence was unable to detect this German regrouping in a timely manner. The appearance of six new German panzer divisions was discovered by the 1st Ukrainian Front only in the course of the operation that had already begun. All told, on the eve of the Soviet attack on 4 March 1944, the German forces numbered 314,066 troops, 449 tanks, assault guns and self-propelled guns, some of which were in temporary repair, and 245 armoured personnel carriers. The 1st Panzer Army itself had 43 tanks and 50 assault guns. In addition, there were over 150 armored vehicles that were in the long term repair as a result of the damage sustained during the Battle of the Korsun-Cherkassy Pocket. Despite this, the 1st and 4th Panzer armies were the most powerful formations of Manstein's Army Group South. 1st phase of the operation: 4–21 March 1944 Main direction: Battle of the Tarnopol-Proskurov railroad At 8 am on 4 March 1944, after massive artillery bombardment, the troops of the Soviet 60th and 1st Guards armies went on the offensive. Infantry and tanks broke through the first line of German fortifications. To develop success in the 60th Army's sector, the 4th and 3rd Guards Tank Armies were introduced. In the first two days of the offensive, the troops of the shock group of the 1st Ukrainian Front overcame the German defenses on the 180-kilometer front and advanced 25 to 50 km. During the initial advance, the Soviet troops did not simply push the Germans back, but intercepted their escape routes. A group of German troops was surrounded and defeated in the area of Mokeevtsy (12 km south of Shepetivka), while under Teofipol (20 km south-east of Yampol), the Soviet units had surrounded and destroyed