By March 1941 their strength was 3,500 men.[301][302] In July 1941, they were assigned to the Pripyat swamps punitive operation, tasked with rounding up and exterminating Jews and partisans.[303] The two regiments were amalgamated into the SS Cavalry Brigade on 31 July, twelve days after the operation started.[304] Fegelein's final report, dated 18 September 1941, states that they killed 14,178 Jews, 1,001 partisans, and 699 Red Army soldiers, with 830 prisoners taken.[305][306] The historian Henning Pieper estimates the actual number of Jews killed was closer to 23,700.[307] The SS Cavalry Brigade took serious losses in November 1941 in the Battle of Moscow, with casualties of up to 60 per cent in some squadrons.[308] Fegelein was appointed as commander of the 8th SS Cavalry Division Florian Geyer on 20 April 1943.