SEOUL: A South Korean soldier was killed Friday and six others injured in an explosion during an artillery firing drill, reports said. Seven servicemen were taken to hospital after the blast at a shooting range in Cherwon, on the border with North Korea, the South’s Yonhap news agency cited an army officer as saying, with one dying during treatment. An investigation into the cause was underway, he added. South Korea remains technically at war with the North after the 1950-53 Korean War ended with an armistice rather than a peace treaty, and it maintains conscription to ensure that it has large numbers of trained soldiers available in the event of conflict. All able-bodied South Korean men must serve in the military for at least 21 months between the ages of 18 and 35. Large-scale joint exercises with the United States military, known as Ulchi Freedom Guardian, are due to begin on Monday.