South Korea has conducted live-fire military drills from five islands near its disputed sea boundary with North Korea, despite Pyongyang's threat to attack.

South Korea reported no immediate action by the North following the drills, which ended after about two hours.

The drills took place in an area of the Yellow Sea that was the target of a North Korean artillery attack in 2010 that killed four South Koreans and raised fears of a wider conflict.

The heightened tension comes two months after the death of North Korean leader Kim Jong Il. His young son Kim Jong Un has taken the helm of the nation of 24 million.

South Korean military officials said they were ready to repel any attack. Residents on the frontline islands were asked to go to underground shelters before the drills started, according to South Korea's defence ministry and joint chiefs of staff.

North Korea's military maintained increased vigilance during the South Korean drills, though it had not done anything suspicious, a South Korean joint chiefs of staff officer said.

Before the drills began, North Korea said it would launch a "thousands-fold more severe" punishment than the 2010 shelling if South Korea conducted the drills.

North Korea is fully prepared for a "total war" and the drills will lead to a "complete collapse" of ties between the Koreas, the North's Committee for the Peaceful Reunification of Korea said in a statement carried by the official Korean Central News Agency.

Seoul is closely monitoring North Korea's reaction. The Korean peninsula has been technically at war for about 60 years. Officials from North Korea and the United States are to meet this week in Beijing for talks on the country's nuclear weapons programme. The discussions will be the first such bilateral contact since Kim Jong Il's death on December 17.

Ties between the Koreas plummeted following the 2010 shelling of front-line Yeonpyeong Island and a deadly warship sinking blamed on Pyongyang. North Korea has denied its involvement in the sinking, which killed 46 South Korean sailors.