New Delhi, Oct. 6 -- The announcement came days after North Korea denied responsibility for the Sept. 21 blasts and threatened "merciless" retaliation if provoked over the case. It followed South Korea's earlier, preliminary finding that said there was a "very high possibility" that mines buried by North Korea caused the explosions.

On Monday, South Korea's Joint Chiefs of Staff said it reached a final conclusion that North Korean mines planted just south of the border exploded and injured the three soldiers who were working on creating a patrol route in a densely vegetated area. It cited a joint investigation of the site with the American-led U.N. Command, forensic analysis of TNT and other substances collected from the South Korean sol...