The South Korean government has promised a firm response to the artillery shelling of one of its islands.
President Lee Myung-bak criticised the North Korean decision to fire on unarmed civilians as “unforgivable”.
This latest cross-border conflict is one of the most significant acts of aggression since the Korean War ended in 1953.
Over 80 shells were fired by North Korea, striking a military unit, killing several marines and setting houses alight.
Local TV footage showed residents on the island seeking cover from the shellfire.
Yeonpyeong is one of South Korea’s border islands and lies 120 kilometres west of the capital, Seoul, but only 12 kilometres away from North Korea.
The extent of the destruction was clearly visible from the mainland, with smoke and fire peppering the mountains.
North Korea has insisted that the South sparked the situation by firing shells, but Seoul maintains that they were conducting military exercises.
Analysts now predict that this latest cross-border incident, which has already involved an exchange of over 100 shells, is the result of unresolved tensions from the loss of a South Korean warship in March.
At the time the South blamed the North, who denied any involvement.