(CNN) -- While the United Nations' Security Council wrangled over growing tensions in the Korean peninsula, South Korea ordered thousands to find shelter in preparation for the South's planned live-fire military exercises, which could take place within hours, the military announced.
In South Korea, an approximate 8,000 residents have been ordered to take cover in Yeonpyeong, Baengnyeong, Daecheong, Socheong and Udo as the hours draw closer to South Korea's military drill, scheduled to take place at 11 p.m. EST Sunday, 1 p.m. Monday local time.
North Korea said over the weekend that the planned exercises were designed to violate the armistice that ended the Korean War in 1953 and "ignite war at any cost."
At the United Nations, nearly eight hours of emergency Security Council talks on the standoff ended Sunday without a unified statement.
Susan Rice, the U.S. Ambassador to the United States said Sunday that council members still cannot bridge any difference over North Korea's November 23rd attack on Yeonpyeong island. Four South Koreans were killed in the attack. The United States has publicly condemned the attacks by the Communist north and insists on South Korea's right to conduct its scheduled military drill.
"The planned exercises are fully consistent with South Korea's legal right to self-defense," Rice said.
"It has been done and notified transparently, responsibly, and will not occur in a fashion that we believe gives North Korea any excuse to respond in the fashion that it has threatened to do."
Russian Ambassador Vitaly Churkin -- who called for the emergency session over the weekend to defuse the crisis -- warned darkly that the world could be faced with a "serious conflict" within hours, and that the international community has "no game plan on the diplomatic side."
"Within hours there may be a serious aggravation of tension -- a serious conflict, for that matter," he said.
Churkin told reporters that Moscow continues to call for restraint on both sides, but said the Security Council had been "not entirely successful" in reaching consensus among its 15 members. He disclosed few details of the session, but said members disagreed over whether to include a condemnation of the North Korean shelling, which left four dead.
Across the Demilitarized Zone, the heavily fortified border set up by the 1953 armistice, South Korean workers were being barred from entering the Kaesong Industrial Complex, the country's Unification Ministry reported. The factory district is the last remnant of South Korea's "Sunshine Policy" of encouraging links with the communist North.
Bill Richardson, the former U.S. ambassador to the United Nations, said Monday he was "extremely worried" that North Korea will respond militarily to the exercises.
Richardson has been meeting with high-level officials on an unofficial, four-day trip to North Korea.
Russia requested Sunday's emergency Security Council meeting and proposed a draft statement, proposing amendments which Western nations said would place more of the blame on North Korea, diplomats said. But they said the major holdout was China, the North's closest ally, which refuses to agree on any statement that even mentions the Yeonpyeong shelling.
Russia and China, both permanent Security Council members, have asked South Korea to reconsider its planned drills. Sunday's closed-door session was held with representatives of both North and South Korea present and speaking.
Earlier, a South Korean military official told the country's state-run Yonhap news agency that Seoul would not be deterred by threats from the North.
"The planned firing drill is part of the usual exercises conducted by our troops based on Yeonpyeong Island. The drill can be justifiable, as it will occur within our territorial waters," the official said.
Tensions between the two Koreas have been high since the North fired upon the island last month, killing two marines and two civilians. The South Korean military had said Thursday that the exercises would take place in the seas southwest of the island between December 18 and 21, but adverse weather forced a delay Saturday.
"We won't take into consideration North Korean threats and diplomatic situations before holding the live-fire drill. If weather permits, it will be held as scheduled," the military official said.
Meanwhile, North Korea was beefing up its military forces on its west coast ahead of the South's planned drills, Yonhap reported, citing a South Korean government official.
"The North Korean artillery unit along the Yellow Sea has raised its preparedness level," the source said.
Yeonpyeong is located in the Yellow Sea, just south of the Northern Limit Line -- the maritime boundary drawn in 1953 by the United Nations just after the Korean War. The line is three nautical miles from the North Korean coast.
In the absence of a full peace agreement between the two Koreas, the Northern Limit Line remains in place. North Korea has suggested an alternative line, but South Korea has resisted, as it would bring the North's maritime boundary close to Incheon, a main port.
A North Korean spokesman over the weekend said that the planned military exercises were a "sinister design" to violate the Korea Armistice Agreement and "ignite war at any cost."
"The shelling to be perpetrated by the puppet forces of south Korea at last, trespassing on the prohibiting line would make it impossible to prevent the situation on the Korean Peninsula from exploding and escape its ensuing disaster," the spokesman said, according to North Korea's official Korean Central News Agency.
North Korea blamed the United States for allegedly egging on the South Koreans.
North Korea "will force the U.S. to pay dearly for all the worst situations prevailing on the peninsula and its ensuing consequences," the spokesman said.
CNN's Jiyeon Lee in Seoul and Richard Roth and Whitney Hurst at the United Nations contributed to this report.