South Korean army soldiers walk on the way to returning to their base after a patrol, in Paju, south of the demilitarized zone that divides the two Koreas, South Korea, Friday, Aug. 21, 2015. South Korea fired dozens of shells Thursday at rival North Korea after the North lobbed several rounds across the world’s most heavily armed border and threatened to take further action unless Seoul ends its loudspeaker broadcasts. The North denied it fired any shots and warned of retaliation for what it called a serious provocation. (AP Photo/Ahn Young-joon)