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

The incident on Tuesday afternoon in the eastern section of the Demilitarised Zone may well have been accidental, according to South Korean media reports.

South Korea’s military said in a statement that about 10 North Korean soldiers returned to the North after South Korea made warning broadcasts and fired warning shots. It said the North Korean soldiers violated the military demarcation line at the eastern section of the border at 5 p.