The T-60 light tank was an evolution from the T-40 series. Designed as a two-man combat vehicle, the T-60 was initially armed with a machine gun in the turret, but this was up-gunned to a 20mm weapon. The T-60 entered production shortly after the invasion of the Soviet Union by Nazi Germany. While these light tanks were no match for the German armor flowing across the border, Soviet planners continued production of the T-60 as a support vehicle since the factory was not equipped to produce the larger/heavier T-34 medium tank. As production continued, efforts were made to further up-gun the main armament, first to 37mm and then 45mm and these design changes were incorporated into the next evolutionary step in the series, the T-70.