Passage: German armies invaded the Soviet Union on 22 June 1941, initiating nearly four years of total war. The Axis initially advanced against desperate but unsuccessful efforts of the Red Army. In the encirclement battle of Kiev, the city was acclaimed as a "Hero City", because of its fierce resistance. More than 600,000 Soviet soldiers (or one-quarter of the Soviet Western Front) were killed or taken captive there, with many suffering severe mistreatment.Although the majority of Ukrainians fought in or alongside the Red Army and Soviet resistance, in Western Ukraine an independent Ukrainian Insurgent Army movement arose (UPA, 1942). Created as armed forces of the underground (Organization of Ukrainian Nationalists, OUN) which had developed in interwar Poland as a reactionary nationalist organization. During the interwar period, the Polish government's policies towards the Ukrainian minority were initially very accommodating, however by the late 1930s they became increasingly harsh due to civil unrest. Both organizations, OUN and UPA supported the goal of an independent Ukrainian state on the territory with a Ukrainian ethnic majority. Although this brought conflict with Nazi Germany, at times the Melnyk wing of the OUN allied with the Nazi forces. Also, UPA divisions carried out massacres of ethnic Poles, which brought reprisals. After the war, the UPA continued to fight the USSR until the 1950s. At the same time, the Ukrainian Liberation Army, another nationalist movement, fought alongside the Nazis.

Question: What percentage of the soviet soldiers were either captured or killed?
one-quarter