U.S Warns N. Korea Of "Consequences"

Secretary of State Hillary Rodham Clinton is warning that North Korea will face consequences because of "provocative and belligerent" actions that include threatened military attacks against U.S. and South Korean warships.

Clinton also underscored Wednesday the U.S. commitment to defend South Korea and Japan in the aftermath of North Korea's nuclear and missile tests this week. She said that talks at the United Nations "are going on to add to the consequences that North Korea will face." She did not provide specifics.

Meanwhile, White House spokesman Robert Gibbs said Wednesday that North Korea's threats against South Korea will not give it the attention Pyongyang wants and will only add to its isolation.

North Korea threatened military action Wednesday against U.S. and South Korean warships plying the waters near the Koreas' disputed maritime border, raising the specter of a naval clash just days after the regime's underground nuclear test.

Pyongyang, reacting angrily to Seoul's decision to join an international program to intercept ships suspected of aiding nuclear proliferation, called the move tantamount to a declaration of war. The threats raise the specter of a naval clash just days after the regime's underground nuclear test.

"Now that the South Korean puppets were so ridiculous as to join in the said racket and dare declare a war against compatriots," North Korea is "compelled to take a decisive measure," the Committee for the Peaceful Reunification of Korea said in a statement carried by state media.

Seoul's decision comes at a time when "the state of military confrontation is growing acute and there is constant danger of military conflict," the statement warned.

South Korea's military said Wednesday it was prepared to "respond sternly" to any North Korean provocation.

North Korea's latest belligerence comes as the U.N. Security Council debates how to punish the regime for testing a nuclear bomb Monday in what President Barack Obama called a "blatant violation" of international law.

Ambassadors from the five permanent veto-wielding council members - the United States, Russia, China, Britain and France - as well as Japan and South Korea were working out the details of a new resolution.

CBS News foreign affairs analyst Pamela Falk reports from the U.N. that the ideas circulating include strengthening sanctions or adding elements of an earlier resolution which called on states to take cooperative action to prevent illicit trafficking in nuclear materials.

"All eyes are on the Security Council, because no one thinks the U.S. can do this alone," Falk said.

Susan Rice, the U.S. ambassador to the U.N., told CBS Early Show co-anchor Harry Smith the North Korean regime, "needs to understand that its actions have consequences. The international community, the United States, Russia, China, Japan, South Korea, we're not going to walk away and just throw up our hands and say, 'Let them pursue this path.' They will pay a price for their actions."

Rice said she expected the coming meeting of the Security Council to yield a new resolution on Pyongyang which she believes "will have teeth in it.

"I expect additional sanctions. The pressure will increase on North Korea, economically and otherwise," the ambassador told Smith.

Asked whether the reclusive communist nation's defiance during the previous 48 hours had prompted the Obama administration to more seriously consider a military response, Rice told CBS News the government would "take the steps that are necessary to protect our country and our people.

For meaningful sanctions, however, the Security Council will have to convince China, traditionally softer in its approach to North Korea, of the need for firmer action.

CBS News correspondent Barry Petersen reports that Beijing is having to tread very carefully in how it deals with its suddenly-more-belligerent ally. North Korea is presently a huge importer of Chinese goods, but that cross-border flow could turn into a flood of North Korean refugees seeking safety in China if tensions escalate too far. (Click here to read more from Petersen.)

"It's not going too far to say that China holds the keys on sanctions," said Kim Sung-han, an international relations professor at Seoul's Korea University.

South Korea, divided from the North by a heavily fortified border, had responded to the nuclear test by joining the Proliferation Security Initiative, a U.S.-led network of nations seeking to stop ships from transporting the materials used in nuclear bombs.

Seoul previously resisted joining the PSI in favor of seeking reconciliation with Pyongyang, but pushed those efforts aside Monday after the nuclear test in the northeast.

North Korea warned Wednesday that any attempt to stop, board or inspect its ships would constitute a "grave violation."

The regime also said it could no longer promise the safety of U.S. and South Korean warships and civilian vessels in the waters near the Korea's western maritime border.

"They should bear in mind that the (North) has tremendous military muscle and its own method of strike able to conquer any targets in its vicinity at one stroke or hit the U.S. on the raw, if necessary," it said.

The maritime border has long been a flashpoint between the two Koreas. North Korea disputes the line unilaterally drawn by the United Nations at the end of the Koreas' three-year war in 1953, and has demanded it be redrawn further south.

The truce signed in 1953 and subsequent military agreements call for both sides to refrain from warfare, but doesn't cover the waters off the west coast.

North Korea has used the maritime border dispute to provoke two deadly naval skirmishes - in 1999 and 2002.

On Wednesday, the regime promised "unimaginable and merciless punishment" for anyone daring to challenge its ships.

Pyongyang also reportedly restarted its weapons-grade nuclear plant, South Korean media said.

The Chosun Ilbo newspaper said U.S. spy satellites detected signs of steam at the North's Yongbyon nuclear complex, an indication it may have started reprocessing nuclear fuel. The report, which could not be confirmed, quoted an unidentified government official. South Korea's Yonhap news agency also carried a similar report.

The move would be a major setback for efforts aimed at getting North Korea to disarm.

North Korea had stopped reprocessing fuel rods as part of an international deal. In 2007, it agreed to disable the Yongbyon reactor in exchange for aid and demolished a cooling tower at the complex.

The North has about 8,000 spent fuel rods which, if reprocessed, could allow it to harvest 13 to 18 pounds of plutonium - enough to make at least one nuclear bomb, experts said. North Korea is believed to have enough plutonium for at least a half dozen atomic bombs.

Further ratcheting up tensions, North Korea test-fired five short-range missiles over the past two days, South Korean officials confirmed.

Russia's foreign minister said world powers must be firm with North Korea but take care to avoid inflaming tensions further.

The world "must not rush to punish North Korea just for punishment's sake," Foreign Minister Sergey Lavrov said, adding that Russia wants a Security Council resolution that will help restart stalled six-nation talks over North Korea's nuclear programs and will not provoke Pyongyang into even more aggressive activity.

South Korean President Lee Myung-bak urged officials to "remain calm" in the face of North Korean threats, said Lee Dong-kwan, his spokesman.

Pyongyang isn't afraid of any repercussions for its actions, a North Korean newspaper, the Minju Joson, said Wednesday.

"It is a laughable delusion for the United States to think that it can get us to kneel with sanctions," it said in an editorial. "We've been living under U.S. sanctions for decades, but have firmly safeguarded our ideology and system while moving our achievements forward. The U.S. sanctions policy toward North Korea is like striking a rock with a rotten egg."