US, South Korea launch war games in tense Yellow Sea

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.