Seoul, Sept. 30 -- South Korea demanded an apology from North Korea on Wednesday over a landmine blast inside the Demilitarized Zone (DMZ) that injured three South Korean soldiers, as Pyongyang rejected Seoul's "fabricated findings" and warned of "immediate and merciless" retaliation if its troops were fired upon.

The US-led United Nations Command (UNC), which oversees the 1953 armistice that halted fighting in the Korean War, said its joint investigation with South Korea has determined that an Armistice Agreement violation has occurred and identified another active North Korean anti-personnel mine on the southern side of the Military Demarcation Line (MDL).

"Based on the findings of the investigation, UNC determined that an Armistice Agr...