(AP Photo/Ahn Young-joon)
Marines will conduct the one-day artillery drills on Yeonpyeong Island -- shelled by a North Korean artillery barrage last month -- and the exact timing will depend on weather conditions, an officer at the Joint Chiefs of Staff said.
South Korea's military will "immediately and sternly" deal with any possible provocation by North Korea, the officer said, speaking on condition of anonymity citing department rules.
Residents, local officials and journalists on the island were ordered to evacuate to underground shelters because of possible attacks by North Korea. Residents of four other front-line islands also were ordered to take shelter, said Won Ji-young, a spokesman for Ongjin County.
The Defense Ministry said the artillery drills were to be staged sometime Monday afternoon. The drills were to last about two hours and involve several types of weapons, including K-9 self-propelled guns, ministry spokesman Kim Min-seok told reporters, according to his office.
The North has warned of a "catastrophe" if South Korea goes ahead with the drills.
The North has said it would strike back harder than it did last month, when two South Korean marines and two civilians were killed on the island.
The U.N. Security Council failed Sunday to agree on a statement to address rising tensions on the Korean peninsula.
U.S. ambassador Susan Rice said the United States and other council members demanded that the council condemn North Korea for two deadly attacks this year that have helped send relations to their lowest point in decades.
But diplomats said China strongly objected.
After eight hours of closed-door consultations Sunday, Russia's U.N. ambassador Vitaly Churkin, who called the emergency council meeting, told reporters "we were not successful in bridging all the bridges."
Although some countries still need to consult capitals, Rice said "the gaps that remain are unlikely to be bridged."
Several bloody naval skirmishes have occurred along the disputed western sea border between the two Koreas in recent years, but last month's assault was the first by the North to target a civilian area since the end of the 1950-53 Korean War. The North does not recognize the U.N.-drawn sea border in the area.
The North claims South Korea fired artillery toward its territorial waters before it unleashed shells on the island on Nov. 23. The South says it launched shells southward, not toward North Korea, as part of routine exercises.
New Mexico Gov. Bill Richardson, a frequent unofficial envoy to North Korea and former U.S. ambassador to the U.N., has held three meetings with top leaders in the foreign ministry and military during a four-day visit to Pyongyang. He called for maximum restraint.
According to South Korea's Yonhap news agency, North Korea has raised military readiness of its artillery unit along the west coast.
It cited an unidentified South Korean government official who was also quoted as saying some North Korean fighter jets that had been inside the air force hangar in the west coast also came out to the ground.
A South Korean Defense Ministry official declined to confirm the report, citing the issue's sensitivity. He asked not to be identified as he was not authorized to speak to the media.
China, the North's key ally, has said it is "unambiguously opposed" to any acts that could worsen already-high tensions.
Chinese Foreign Minister Yang Jiechi and his Russian counterpart, Sergei Lavrov, called for restraint from all parties concerned to avoid escalation, according to China's official Xinhua News Agency.
About 240 residents, officials and journalists remain on Yeonpyeong, said Lim Byung-chan, an official from Ongjin County, which governs the island. He said there is no immediate plan to order a mandatory evacuation to the mainland.
Amid security jitters, nearly 800 out of 1,300 civilians living on the island moved to unsold apartments in Gimpo, west of Seoul, on Sunday, according to Ongjin County officials.