North Korea has begun building walls near the demilitarized zone near the border with South Korea, the reasons for the construction are unknown.

Construction work began recently in a two-kilometer stretch between the North's demilitarized zone and the cease-fire line separating the two countries. South Korean troops fired warning shots after North Korean soldiers briefly crossed the ceasefire line using pickaxes and shovels. Tensions between the two countries escalated, and North Korea sent balloons filled with garbage to the South in retaliation for leaflets and USB sticks dropped on the North by South Korean activists.