North Korea attack 'unprecedented'

A prominent academic has told SBS's Senior Correspondent Brian Thomson that Pyongyang's deadly attack on a South Korean island was 'unprecedented' because of the nature of the casualties.

Professor Chung-in Moon from Yonsei University says Seoul has previously suffered casualties from recent tensions with its northern neighbour, but this is the first time residents have died on land.

"It has characteristics of military war, rather than just skirmishes," Professor Chung-in says.

Pyongyang says it acted in self-defence by lauching the attack, but the leading analyst says it is difficult to ascertain the real reason behind it.