SEOUL, South Korea — Following weeks of investigation, leaked evidence and diplomatic huddles, South Korea on Thursday publicly accused North Korea of firing a torpedo that sank a naval patrol ship and killed 46 crewmen in March, significantly raising the security stakes on an already tense Korean Peninsula.
The international community responded with concern and condemnation for Kim Jong Il's isolationist regime. United Nations Secretary-General Ban Ki-moon called the case "deeply troubling," and Australian Prime Minister Kevin Rudd insisted that the North's "hostile and unprovoked act" should be met with swift and immediate retaliation.
Yet troublesome questions remain: What response can the South and its allies, including the U.S., give to warn North Korea against further provocations without inciting continued violence? Denying culpability, Pyongyang has already rattled its sabers, warning that any retaliation would lead to "all-out war."
The U.S Thursday stood behind South Korea, with the White House issuing a statement that said the "act of aggression is one more instance of North Korea's unacceptable behavior and defiance of international law."
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Citing what it called overwhelming evidence, a joint civilian-military multinational team determined that fragments and markings from a torpedo found amid the wreckage of the downed naval vessel matched that of a North Korean-made weapon already in the South's possession.
The report concluded that "there is no other plausible explanation" than the North's involvement.
North Korea on Thursday called the probe's findings a "fabrication" and said it would send its own inspection team to the South to consider the evidence, according to a statement released through the North's state-run Korean Central News Agency. It wasn't clear whether the South would allow such a trip.
Analysts predict that the cold war between North and South is about to get a lot colder.
"While a military war is less likely, I think an all-out economic war is certain," said Ahn Yin-hay, an international studies professor at Korea University in Seoul. "Relations between North and South will reach a stalemate. The U.S. may even put North Korea on its terrorist list again. But all this means that relations between the U.S. and South Korea with be strengthened."
South Korean President Lee Myung-bak has vowed to take "stern action," including severing most or all economic aid to the North. Lee called an emergency security meeting for Friday, pledging to augment naval forces and sensors along the disputed maritime boundary between North and South where the sinking occurred.
South Korea said it would also ask the U.N. Security Council to issue a strong rebuke and impose financial penalties against Pyongyang.
Still, there remains no worldwide consensus on how or even whether to punish North Korea, with China seemingly unwilling to fully commit to sanctions.
Cui Tiankai, China's vice minister of foreign affairs, on Thursday called the Cheonan sinking "unfortunate," but stopped short of backing Seoul in the dispute. He instead reiterated the need to maintain peace on the Korean Peninsula.
Fearing that a collapse of the neighboring regime would wreak havoc along its border, China has walked a delicate line with the North, refusing to turn its back on a longtime ally, analysts say.
"China has always been the weak link in punishing Pyongyang, and Beijing will react with its customary call for caution and restraint," said Bruce Klingner, a northeast Asia expert at the Heritage Foundation think tank in Washington. "But a blatant North Korean provocation such as the sinking of the Cheonan could provide South Korea and the U.S. with sufficient leverage to get Beijing to agree to some stronger measures against North Korea."
During a trip to Beijing earlier this month, Kim reportedly failed to receive the customary assurances of continued economic aid, a sign that China's unconditional support for its neighbor may be weakening.
South Korean scholars say the hard evidence of a North Korean torpedo may force China's hand.
"It will be very hard for China to oppose (punishing the North) because of the smoking gun," said Yun Duk-min, a professor at the Institute of Foreign Affairs and National Security in Seoul. "China is now puzzled and in an awkward situation."
Korea University's Ahn said China has to be sensitive to North Korea's needs.
"China is the only country that can support North Korea from collapse," she said. "And Beijing officials know that in order to maintain its influence on the Korean Peninsula, they have to hear out North Korea's demands."
Analysts say the stormy political waters stirred up by the Cheonan controversy will delay any restart of the six-nation talks to disarm North Korea's nuclear arsenal. North Korea abandoned the talks in late 2008 and has since conducted at least one underground nuclear test.
"The six-party talks have gone down the drain," said Kim Keun-sik, a political science professor at Kyungnam University outside Seoul. "China will not support South Korea on (the Cheonan) matter. So, we're back to North Korea and China versus South Korea and the U.S.
"The landscape of confrontation during the Cold War era is expected to appear again."