The Vyborg massacre was the killing of approximately 360-420 Russians in the town of Vyborg during the Finnish Civil War in April–May 1918. The massacre took place during and after the Battle of Vyborg as the White Guards captured the town from the Red Guards. At least half of the victims were Russian soldiers and military personnel. The slain were mainly men and young boys: nine out of ten were men fit for military service. The White Guards were "cleansing" the city of Red Guards, however, only a small minority of the killed Russian townsfolk were affiliated with the Finnish labour movement.