South Korea fired warning shots after, Seoul says, North Korean troops crossed their border. The soldiers then went back to the North, Seoul said.

Observers claimed the Pyongyang troops might have mistakenly crossed the boundary while fortifying their side with anti-tank barriers or mines.

The South Korean military fired several warning shots after about a dozen North Korean soldiers crossed into its territory. According to South Korea’s Joint Chiefs of Staff, the North Korean soldiers turned back after hearing warning messages broadcast over loudspeakers.