A South Korean soldier stands on a military guard post near the demilitarized zone (DMZ) dividing the two Koreas in the border city of Paju on April 5, 2013. The United States said it was taking "all necessary precautions" after North Korea rang fresh alarms in an escalating crisis by moving a medium-range missile to its east coast. AFP PHOTO / JUNG YEON-JE (Photo credit should read JUNG YEON-JE/AFP/Getty Images)