South Korea holds live-fire drills near sea border with North South Koreans in a bomb shelter on the border island of Baengnyeong during live-fire drills by their military. Photograph: AFP/Yonhap 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 North Korea following the drills, which ended after about two hours. They 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 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. Before the drills began, North Korea said it would launch a "thousands-fold more severe" punishment than the 2010 shelling if South Korea went ahead. North Korea was fully prepared for a "total war," and the drills would 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 on Monday by the North's official Korean Central News Agency. Officials from North Korea and the US are to meet this week in Beijing for talks on the country's nuclear weapons program. The discussions will be the first such bilateral contact since Kim Jong-il's death on 17 December. Ties between the Koreas plummeted after the 2010 shelling of frontline Yeonpyeong Island and a deadly warship sinking blamed on Pyongyang. North Korea has flatly denied its involvement in the sinking, which killed 46 South Korean sailors. In Monday's exercise South Korean troops on the five islands fired artillery into waters southward, away from North Korea, a defence ministry official said. South Korea's military was ready to repel any North Korean provocation, the official said on condition of anonymity, citing department rules. More than 1,000 residents on the islands, many of them elderly, filed into underground bomb shelters and huddled around portable heaters during the drills. Few came to the mainland despite the North Korean threat, according to Onjin county, which governs the islands. Ferry services linking the islands and Incheon port on the mainland operated normally, county officials said, adding that requests to evacuate were made each time South Korea conducted drills. Soon after Seoul told Pyongyang of its live-fire training plans on Sunday, North Korea's military called the drills a "premeditated military provocation" and warned it would retaliate for an attack on its territory. A North Korean officer warned in an interview with the Associated Press in Pyongyang that North Koreans were always ready to "dedicate their blood to defend their inviolable territory." If they provoke us there will be only merciless retaliatory strikes," officer Sin Chol Ung from the North's Korean People's Security Forces said on Sunday. Three deadly naval clashes since 1999 have taken a few dozen lives in the waters contested by the two Koreas. The maritime line separating the countries was drawn by the US-led UN Command without Pyongyang's consent at the close of the 1950-53 Korean War. North Korea routinely argues that the line should run farther south.