 Complete the following phrase:  On 26 August German 2nd Panzer Group secured a bridgehead on the Desnas eastern bank near Novhorod-Siverskyi which threatened the eastern flank of 21st Army. Kuznetsov ordered a withdrawal over the river Desna. Unfortunately Kuznetsov did not inform the neighbouring Soviet units about his decision. Because of that 40th Army was forced to abort its attack on the German bridgehead near Novhorod-Siverskyi and the army commander, Major-General Kuzma Podlas, ordered a retreat to the southeast. Thus 21st Army, between South Western Fronts 40th and 5th Armies was cut off from the forces of Bryansk Front. Kuznetsov cant be blamed for that decision because his army was at that point already beaten by German forces and in full retreat. In this situation on 6 September Kuznetsovs army was placed under the command of Southwestern Front. By then the advance by 2nd Panzer Group had forced a gap between South Western Front and Bryansk Front, and 21st Army, continuing to retreat to the south, became caught up in a vast encirclement that became the 