New tension in the Korean peninsula as US / South Korean War games begin.

YEONPYEONG ISLAND, South Korea – A U.S. supercarrier and South Korean destroyer took up position in the tense Yellow Sea on Sunday for joint military exercises that were a united show of force just days after a deadly North Korean artillery attack.

As tensions escalated across the region, with North Korea threatening another "merciless" attack, China belatedly jumped into the fray. Beijing's top nuclear envoy, Wu Dawei, called for an emergency meeting in early December among regional powers involved in nuclear disarmament talks, including North Korea.

Seoul responded cautiously to the proposal from North Korea's staunch ally, saying it should be "reviewed very carefully" in light of North Korea's recent revelation of a new uranium-enrichment facility, even as protesters begged President Lee Myung-bak to find a way to resolve the tension and restore peace.

The troubled relations between the two Koreas, which fought a three-year war in the 1950s, have steadily deteriorated since Lee's conservative government took power in 2008 with a tough new policy toward nuclear-armed North Korea.

Eight months ago, a South Korean warship went down in the western waters, killing 46 sailors in the worst attack on the South Korean military since the Korean War. Then, last Tuesday, North Korean troops showered artillery on Yeonpyeong, a South Korean-held island that houses military bases as well as a civilian population of 1,300 — an attack that marked a new level of hostility.

Two South Korean marines and two civilians were killed and 18 others wounded in the hailstorm of artillery that sent residents fleeing into bunkers and reduced homes on the island to charred rubble.

North Korea blamed the South for provoking the attack by holding artillery drills near the Koreas' maritime border, and has threatened to be "merciless" if the current war games — set to last until Dec. 1 — get too close to its territory.

As U.S. and South Korean ships, including the nuclear-powered USS George Washington, sailed into the waters off Korea's west coast Sunday, China began launching its diplomatic bid to calm tensions.

Washington and Seoul had been pressing China, North Korea's main ally and benefactor, to help defuse the situation amid fears of all-out war.

China, slow at first to react, has quickened its diplomatic intervention in recent days. Chinese state councilor Dai Bingguo made a last-minute visit to Seoul to confer with Lee.

Lee pressured China to contribute to peace in a "more objective, responsible" matter, and warned Sunday that Seoul would respond "strongly" to any further provocation, the presidential office said.

The strong words were Lee's first public comment in days. He was due to address the nation Monday morning amid calls from his people to take stronger action in dealing with the defiant North.

North Korea has walked a path of defiance since launching a rocket in April 2009 in violation of U.N. Security Council resolutions and abandoning the disarmament process in protest against the condemnation that followed.

However, in recent months Pyongyang has shown an eagerness to get back to the talks, and has appeared increasingly frustrated by U.S. and South Korean reluctance to restart the negotiations.

Seoul has said it wants an acknowledgment of regret for the sinking of the Cheonan warship in March as well as a concrete show of commitment to denuclearization.

North Korea, which cites the U.S. military presence in South Korea as a main reason behind its drive to build atomic weapons, routinely calls the joint exercises between the allies a rehearsal for war.

Washington, which keeps 28,500 troops in South Korea to protect the ally, insists the routine drills were planned before last Tuesday's attack.

The exercises will take place over four days, but no live-fire drills are planned, said Cmdr. Jeff Davis, spokesman for the 7th Fleet in Japan.

Along scenic Mallipo Beach on the west coast, about 50 South Korean soldiers were laying down an aluminum road to prepare for an amphibious landing drill Monday. Barbed wire and metal staves ran the length of the beach for about 2 miles (3 kilometers). Military ships hovered in the distance.

North Korea expressed renewed outrage over the Yellow Sea drills.

The war games are a "pretext for aggression and ignite a war at any cost," the National Peace Committee of Korea said in a statement carried Sunday by the official Korean Central News Agency.

Hours earlier, the rattle of new artillery fire from North Korea sent residents, journalists, police and troops scrambling for cover on Yeonpyeong Island. None of the rounds landed on the island, military officials said, but the incident showed how tense the situation remains.

Saying they could not guarantee the journalists' safety, South Korea's Defense Ministry sent a ship to ferry them off the island but bad weather forced them to cancel the evacuation. About 380 people, including 28 islanders and 190 journalists, remained on Yeonpyeong on Sunday, officials said.

A similar burst of artillery fire Friday occurred just as the U.S. military's top commander in the region, Gen. Walter Sharp, was touring Yeonpyeong Island. No shells landed anywhere in South Korean territory.

Calls for tougher action made way Sunday for pleas for peace among about 150 South Koreans who turned out for a vigil Sunday evening in a Seoul plaza, huddling with candles in paper cups and chanting, "Give us peace!"

"It was very shocking," said Kang Hong-koo, 22, a student. "I'm here to appease the souls of the people who were killed in the North Korean attack. I hope the current tense situation is alleviated quickly."

More on the tensions in the Korean peninsula.

SEOUL, South Korea – North and South Korea exchanged artillery fire Tuesday after the North shelled an island near their disputed sea border, killing at least two South Korean marines, setting dozens of buildings ablaze and sending civilians fleeing for shelter.

The skirmish began when Pyongyang warned the South to halt military drills in the area, according to South Korean officials. When Seoul refused, the North bombarded the small South Korean-held island of Yeonpyeong, which houses military installations and a small civilian population.

South Korea returned fire and dispatched fighter jets in response, and said there could be considerable North Korean casualties as troops unleashed intense retaliatory fire. The supreme military command in Pyongyang threatened more strikes if the South crossed their maritime border by "even 0.001 millimeter," according to the North's official Korean Central News Agency.

Government officials in Seoul called the bombardments "inhumane atrocities" that violated the 1953 armistice halting the Korean War. The two sides technically remain at war because a peace treaty was never signed.

The exchange was a sharp escalation of the skirmishes that flare up along the disputed border from time to time, and come amid high tensions over North Korea's claim that it has a new uranium enrichment facility and just six weeks after North Korean leader Kim Jong Il unveiled youngest son Kim Jong Un as his heir apparent.

Columns of thick black smoke could be seen rising from homes on the island in footage aired by YTN cable television. Screams and shouts filled the air as shells rained down on the island for about an hour.

"I thought I would die," Lee Chun-ok, 54, told The Associated Press after being evacuated to the port city of Incheon, west of Seoul. "I was really, really terrified, and I'm still terrified."

She said she was watching TV when the shelling began, and a wall and door in her home suddenly collapsed.

The United States, which has more than 28,000 troops stationed in South Korea, condemned the attack. in Washington, White House Press Secretary Robert Gibbs called on North Korea to "halt its belligerent action," and said the U.S. is "firmly committed" to South Korea's defense, and to the "maintenance of regional peace and stability."

China, the North's economic and political benefactor, which also maintains close commercial ties to the South, appealed to both sides to remain calm and "to do more to contribute to peace and stability on the peninsula, Foreign Ministry spokesman Hong Lei said.

Yeonpyeong, famous for its crabbing industry and home to about 1,200 civilians as well as South Korean military installations, is west of the Korean mainland within sight of North Korean shores. There are about 30 other small islands nearby.

North Korea fired dozens of rounds of artillery in three separate barrages that began in the mid-afternoon, while South Korea returned fire with about 80 rounds, South Korea's Joint Chiefs of Staff said. The entire exchange lasted about an hour.

Two South Korean marines were killed and 16 injured, the Joint Chiefs of Staff said. Island residents escaped to some 20 shelters on the island and sporadic shelling ended after about an hour, according to the military.

The skirmish occurred a day after the South Korean military began holding drills in the area, exercises that North Korea's military demanded an end to early Tuesday, the JCS said.

South Korean marines participating in the drill had been shooting artillery during those drills, but toward southern waters, away from North Korea, a military official said, speaking on condition of anonymity due to military rules.

President Lee Myung-bak ordered officials to "respond sternly" but to refrain from allowing the situation to escalate, according to a presidential official. He asked not to be identified, citing the issue's sensitivity.

Lee was convening an emergency security meeting, the official said.

The Koreans have remained in a technical state of war for decades because their three-year conflict ended in a truce, not a peace treaty, in 1953.

However, North Korea does not recognize the western maritime border drawn unilaterally by the United Nations at the close of the conflict, and the Koreas have fought three bloody skirmishes there in recent years.

In March, a South Korean warship went down in the waters while on a routine patrolling mission. Forty-six sailors were killed in what South Korea calls the worst military attack on the country since the Korean War.

Seoul blamed a North Korean torpedo, but Pyongyang denied responsibility.

North Korea attacks South Korean village, ROK retaliates.

This might mean a renewed conflict that remained dormant for 60 years. The Korean war ended in the longest cease fire in history. This might renew the war.

More as it comes in.

SEOUL, South Korea – North Korea is threatening to continue launching strikes against South Korea if it violates their disputed sea border "even 0.001 millimeter."

North Korea's supreme military command said Tuesday that it would "launch merciless military retaliatory strikes."

The warning was carried by North Korea's official Korean Central News Agency.

The comments followed North Korea's bombardment of a South Korean island near their disputed western border Tuesday. South Korean officials said the barrage set buildings ablaze and killed at least one marine after the North warned the South to halt military drills in the area.