North Korea had urged Seoul to cancel the annual large-scale drills, known as Key Resolve and Foal Eagle, warning of an "unimaginable holocaust" if they went ahead as planned starting late February. (Agencies)
The Committee for the Peaceful Reunification of Korea (CPRK), a North Korean state body in charge of inter-Korean affairs, said Wednesday that staging the exercises would drive the Korean peninsula "into catastrophe".
The joint South Korea-US drills are conducted every year and are routinely condemned by the North as rehearsals for invasion.
Reacting to the latest warning from Pyongyang, South Korea's Defence Ministry insisted the exercises would go ahead as scheduled.
"If North Korea commits military provocations by taking advantage of these routine exercises… the military will retaliate severely and firmly," spokesman Kim Min-Seok told reporters.
Kim also said North Korea would be better off taking "positive steps" towards addressing global concerns over its nuclear weapons programme than lecturing the South on its military drills.
Last year's joint exercises were held in the wake of North Korea's third and largest nuclear test, and prompted months of escalated military tensions that saw Pyongyang issue apocalyptic threats of nuclear strikes against the South and United States.
North-South Korean ties are currently in a state of watchful limbo, with both sides voicing willingness to improve relations while accusing the other of lacking sincerity.
Earlier this month, South Korean President Park Geun-Hye called for the resumption of reunions for families separated by the Korean War. But the North rejected the proposal, citing the planned South-US exercises as a major barrier.
North Korea had urged Seoul to cancel the annual large-scale drills, known as Key Resolve and Foal Eagle, warning of an "unimaginable holocaust" if they went ahead as planned starting late February.