Five years after North Korea fired shells on to a South Korean island, Pyongyang has vowed to retaliate mercilessly should Seoul hold fire drills near the border on the anniversary.

North Korea fired scores of artillery shells at South Korea’s Yeonpyeong island on November 23, 2010, killing four people, including two civilians in one of the heaviest attacks on its neighbour since the Korean War ended in 1953.

North Korea said it was provoked into the attack by South Korean live-fire drills in the area that dropped shells in its territorial waters.

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• North Korea warns of strikes

The threat came after the two nations agreed on Friday to hold talks later this month, setting the stage for the first government-level meeting focused on easing tension since the two pledged to improve ties following an armed standoff in August.

“If the South Korean military fires at the waters of the DPRK in the hotspot area of the West Sea of Korea on Monday, they will experience merciless retaliation of the South-western Front units of the DPRK on the five islands,” North Korea’s official KCNA news agency quoted a military spokesman as saying.

DPRK is an acronym for the North’s official name, the Democratic People’s Republic of Korea.

“They should not dig their own graves with war drumbeats for the pre-emptive strike against the DPRK, but draw a lesson from the bitter defeat they suffered five years ago,” the military command spokesman said.

An official at South Korea’s Joint Chiefs of Staff said they were monitoring the situation but he declined to give further comment.

Impoverished North Korea and rich, democratic South Korea remain technically at war after their 1950-53 conflict ended in a truce, not a treaty.

The North, slapped with UN and US sanctions for its nuclear weapons and rocket programs, often threatens to destroy the South, and its major ally, the United States, in a sea of flames.