the 6th Mechanized Corps' 1,212 tanks, only about 200 reached their assembly areas due to air attacks and mechanical breakdowns, and even they ran out of fuel by the end of the day. The same fate awaited the 243 tanks of the 11th Mechanized Corps, ordered to attack towards Grodno on 25 June. The 6th Cavalry Corps suffered 50% casualties and its commander, Nikitin, was captured. The attempted attack allowed many Soviet forces to escape from the Białystok region towards Minsk, but this brought only temporary relief. With both the German Second and Third Panzer Groups racing towards Minsk on the Western Front's southern and northern flanks, a new encirclement threatened. In the evening of 25 June, the German 47th Panzer Corps cut between Slonim and Vawkavysk, forcing the attempted withdrawal of troops in the salient to avoid encirclement and opening the southern approaches to Minsk. Pavlov dispatched orders to disengage and withdraw into new defences behind the Shchara River, but the few units receiving the orders were unable to break contact with the enemy. Hounded by constant air attacks, Pavlov's forces fled eastward on foot. Most of the 10th Army was not able to cross the river because the bridges over the Shchara were destroyed by air attacks. Further east, the 13th Army, which had received orders to assemble various withdrawing forces into the defence of Minsk, had its headquarters ambushed by German spearheads and its defence plans captured. Pavlov then ordered his 20th Mechanized and 4th Airborne Corps, until then held in reserve, to halt the Germans at Slutsk. However the 20th Mechanized Corps had only 93 older tanks and the 4th Airborne had to deploy on foot from lack of aircraft. Neither proved any threat to the advancing Second Panzer Group. On 27 June 1941, the German Second and Third Panzer Groups striking from south and north linked up near Minsk, surrounding and eventually destroying the Soviet 3rd, 10th and 13th Armies, and portions of the 4th Army, in total about 20 divisions, while the remainder of the 4th Army fell back eastwards toward the Berezina River. On 28 June 1941, the Ninth and Fourth German Armies linked east of Białystok splitting the encircled Soviet forces into two pockets: a larger Białystok pocket containing the Soviet 10th Army and a smaller Navahrudak pocket. In the first 18 days of the war, the Western Front had suffered 417,790