Since the Yeonpyeong shelling in 2010, South Korea has upgraded its defences on frontline islands in the area
North Korea has threatened to repeat its 2010 artillery attack on a border island, as South Korea prepares to mark on Friday the second anniversary of the shelling that left four dead.
The South plans to hold several commemorative events over the next few days on Yeonpyeong island near the disputed Yellow Sea border and will conduct a military drill in the area on Friday.
North Korea heaped scorn on the memorial activities, with the official Korean Central News Agency (KCNA) on Thursday quoting a military spokesman who warned of another attack on the island.
"The commemoration... on Yeonpyeong Island will lead to the second Yeonpyeong Island disaster," the spokesman said.
The November 23, 2010 shelling of the island killed two South Korean marines and two civilians in one of the most serious border incidents since the 1950-1953 Korean War.
The North said the attack was in response to a live-fire drill by the South, which, it claimed, had resulted in shells falling on its side of the sea border.
South Korean troops responded with cannon fire and the government met in an underground war room, fuelling fears that the situation could escalate into a full-scale conflict.
The de facto maritime boundary between the two Koreas -- the Northern Limit Line -- is not recognised by Pyongyang, which argues it was unilaterally drawn by the US-led United Nations forces after the war.
The North Korean spokesman said the South's plans to commemorate the anniversary of the shelling were a "ridiculous farce" that invited derision and censure.
The only regret on the North's side, he said, was that the military had not seized the opportunity two years ago "to send the whole of Yeonpyeong Island to the bottom of the sea.
"It is the steadfast will of the service personnel not to miss the opportunity to do so if the warmongers perpetrate another provocation," he added.
South Korea has stressed that Friday's military drill will not include any live-fire exercises.
Since the Yeonpyeong shelling, South Korea has upgraded its defences on frontline islands in the area.
Yeonpyeong's 1,200 residents, who live just 1.5 kilometres (one mile) from the disputed border, are now outnumbered by the marines posted there.
Last month, President Lee Myung-Bak paid a surprise visit to the island and spoke to the troops about the need to defend the maritime border "to the last man".
On a tour later Thursday of an army command post south of Seoul, Defence Minister Kim Kwan-Jin underlined concerns that Pyongyang might seek to trigger a confrontation ahead of the South's presidential election on December 19.
"North Korea could commit provocative acts in order to inject fears of war into South Koreans before the election," Kim said.
"After the election, it may provoke the South to test the new government and tame it," he said, adding that when "gangsters" attack the only way to respond was with "a large club".
South Korean Marines take part in a military exercise on Yeonpyeong Island in 2011. North Korea has threatened to repeat its 2010 artillery attack on a border island, as South Korea prepares to mark on Friday the second anniversary of the shelling that left four dead.
A general view shows damage caused to buildings on South Korea's Yeonpyeong Island on December 3, 2010 following a North Korean artillery and rocket attack. The South plans to hold several commemorative events over the next few days on Yeonpyeong island near the disputed Yellow Sea border and will conduct a military drill in the area on Friday.
The North Korean shore seen in November 2010 from the South Korean island of Yeongpyeong. North Korean artillery shells were fired from this shoreline at Yeonpyeong killing four people in 2010.