South Korea said North Korean soldiers working inside the Demilitarised Zone (DMZ) were “injured or killed” by exploding mines on June 18. The Joint Chiefs of Staff in Seoul did not say when and where the explosions occurred. South Korean officials said that the country’s forces also fired warning shots near central parts of the border on June 18. This was after dozens of North Korean soldiers briefly crossed the heavily fortified border but retreated after warning shots were fired. Seoul does not think the breach was intentional, the Yonhap news agency reported. This was the second such incident in two weeks as Pyongyang reinforces its frontiers with the South. Watch the video to find out more.