to SS Das Reich by the Fall of 1941). SS Division Nord, which was in northern Finland, took part in Operation Arctic Fox with the Finnish Army and fought at the battle of Salla, where against strong Soviet forces they suffered 300 killed and 400 wounded in the first two days of the invasion. Thick forests and heavy smoke from forest fires disoriented the troops and the division's units completely fell apart. By the end of 1941, Nord had suffered severe casualties. Over the winter of 1941–42 it received replacements from the general pool of Waffen-SS recruits, who were supposedly younger and better trained than the SS men of the original formation, which had been drawn largely from Totenkopfstandarten of Nazi concentration camp guards. The rest of the Waffen-SS divisions and brigades fared better. The SS Totenkopf and Polizei divisions were attached to Army Group North, with the mission to advance through the Baltic states and on to Leningrad. The SS Division Das Reich was with Army Group Centre and headed towards Moscow. The SS Division Wiking and the were with Army Group South, heading for the Ukraine and the city of Kiev. The war in the Soviet Union proceeded well at first, but the cost to the Waffen-SS was extreme: by late October, the was at half strength due to enemy action and dysentery that swept through the ranks. Das Reich lost 60% of its strength and was still to take part in the Battle of Moscow. The unit was decimated in the following Soviet offensive. The Der Führer Regiment was reduced to 35 men out of the 2,000 that had started the campaign in June. Altogether, the Waffen-SS had suffered 43,000 casualties. While the and the SS divisions were fighting in the front line, behind the lines it was a different story. The 1 SS Infantry and 2 SS Infantry Brigades, which had been formed from surplus concentration camp guards of the SS-TV, and the SS Cavalry Brigade moved into the Soviet Union behind the advancing armies. At first, they fought Soviet partisans and cut off units of the Red Army in the rear of Army Group South, capturing 7,000 prisoners of war, but from mid-August 1941 until late 1942 they were assigned to the Reich Security Main Office headed by Reinhard Heydrich. The brigades were now used for rear area security and policing, and were no longer