South Korean Leader Feels Responsible for Attack

South Korea's president on Monday took responsibility for failing to protect South Koreans from a deadly North Korean artillery attack last week, even as he vowed that the North would face consequences for future aggression.

Lee Myung-bak didn't offer specifics about those consequences nor did he say what actions South Korea will take in response to the artillery barrage on Yeonpyeong Island that killed four, including two civilians, and sent tensions soaring in the region.

"I feel deeply responsible for failing to protect my people's lives and property," Lee said. He said he was "very sorry and regretful" for the death of innocent people.

"Launching military strikes against civilians is an inhumane crime that is even banned during wartime," Lee said.

As Lee spoke, a nuclear-powered U.S. supercarrier and a South Korean destroyer participated in joint military exercises that were a united show of force aimed at the North.

North Korea, meanwhile, threatened another "merciless" attack, as South Korean protesters begged Lee to find a way to resolve the tension and restore peace.

For More on Korean Peninsula Tensions:

China Proposes Emergency Talks on Korea Tensions
S. Korea Mourns 2 Marines Killed in N. Korean Attack
N. Korea: We'll Retaliate if Provoked
Obama: We Will Defend South Korea
S. Koreans Recount Attack; 2 More Bodies Found
S. Korean says Attack "Was Like War"
S. Korea Decries "Inhumane Atrocities" in Clash

China, the North's only major ally, has 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 gave a cool response to Beijing's proposal, saying it should be "reviewed very carefully" in light of North Korea's recent revelation of a new uranium-enrichment facility.

The Foreign Ministry said in a statement that the proposal should be "reviewed very carefully" and noted that North Korea's recent revelation of a new uranium-enrichment facility has a "negative effect" on efforts to resume the talks. , could signal an expansion of the North's nuclear weapons program.

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 was slow at first to react after ally North Korea pummeled a South Korean island with an artillery barrage on Tuesday, but has quickened its diplomatic intervention in recent days.

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 the North.

Eight months ago, a South Korean warship went down in 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 steadily threatened to be "merciless" if war games get too close to its territory.