YEONPYEONG ISLAND, South Korea - South Korea ordered residents of front-line islands into bomb shelters as it vowed to press forward with live-fire drills near disputed waters today, despite North Korea's threat to retaliate, sharply spiking tensions.

U.N. diplomats meeting in New York failed to find any solution to ease fears of a new war on the Korean peninsula, nearly a month after the North shelled South Korea's Yeonpyeong island in retaliation for earlier artillery exercises there. The North has said it would respond even more harshly to any new drills from the Yellow Sea island.

South Korea's move to launch new drills from Yeonpyeong brought tensions to their highest point since the North's Nov. 23 bombardment, which killed two South Korean marines and two civilians in the North's first attack targeting civilian areas since the 1950-53 Korean War.

South Korean marines on Yeonpyeong, a tiny enclave of fishing communities and military bases within sight of North Korean shores, were to conduct the live-fire drills from the island later today, although the exact timing would depend on weather conditions, the Joint Chiefs of Staff and the Defense Ministry said.

South Korea's military will "immediately and sternly" deal with any North Korean provocation, a Joint Chiefs of Staff officer said, speaking on condition of anonymity, citing department rules.

Residents, local officials and journalists Yeonpyeong and four other islands were ordered to evacuate to underground shelters because of possible attacks by North Korea, Ongjin County government spokesman Won Ji-young said.

The Defense Ministry said the artillery drills were to last about two hours and involve several types of weapons.

The North, which considers the waters around Yeonpyeong its own territory, has warned of a "catastrophe" if South Korea goes ahead with the drills.