North Korea conducts powerful nuclear test

Enough plutonium for half-dozen bombs
Could have enough putNorth Korea boasted that Monday's test was conducted "on a new higher level in terms of its explosive power and technology of its control."

U.S. and French officials have said the 2006 test measured less than a kiloton; 1 kiloton is equal to the force produced by 1,000 tons of TNT. Russia estimated the force of the 2006 blast at 5 to 15 kilotons, far higher than other estimates at the time.

Pyongyang is believed to have enough weaponized plutonium for at least a half-dozen atomic bombs. However, experts say scientists have not yet mastered the miniaturization needed to mount a nuclear device onto a long-range missile.

"They are still at least several years away from being able to deliver a nuclear device on a weapon," Beck said.

North Korea called its April 5 rocket launch a successful bid to put a satellite into space, but the U.S., Japan, South Korea and others accused Pyongyang of using the launch to test its long-range missile technology. The Security Council condemned the launch as a violation of U.N. resolutions.

"I sincerely hope that the Security Council will take necessary corresponding measures," U.N. Secretary-General Ban Ki-moon told The Associated Press in Copenhagen on Monday, declining to specify what further moves, or sanctions, he would urge the 15 council members to take.

Jim Walsh, an international security expert at the Massachusetts Institute of Technology, said he expected U.N. members to call for sanctions — but dismissed any punishment as "political theater" that would have little effect on a country already subject to numerous sanctions.

'Maximum pressure' on the United States
Obama might be the only one who can give North Korea what it wants.

Paik Hak-soon of the South Korean security think tank Sejong Institute said North Korea is "putting maximum pressure" on the United States for direct, high-level negotiations resulting in a "grand deal" that would include aid, concessions and a normalization of ties.

Video   Mullen on N. Korea's nuclear weapon test May 25: TODAY’s Lester Holt talks to Admiral Mike Mullen, the chairman of the Joint Chiefs of Staff, about North Korea’s apparent nuclear weapons test and the war in Afghanistan. Today show

North Korea also has custody of two American journalists, Laura Ling and Euna Lee — accused of entering the country illegally and engaging in "hostile acts" — who are set to stand trial in Pyongyang on June 4.

Their case may serve as a face-saving way for the U.S. to send a high-level envoy to Pyongyang for negotiations, Paik said.

"Had it not been for the journalists, it could give an impression of yielding to North Korea's provocation if the U.S. sends a high-level envoy for direct talks with Pyongyang," he said.

South Korean troops are on high alert but there was no sign North Korean soldiers were massing along the heavily fortified border dividing the two nations, according to an official at the Joint Chiefs of Staff headquarters in Seoul. He spoke on condition of anonymity, citing agency policy.

The two Koreas technically remain at war because their three-year conflict ended in a truce, not a peace treaty, in 1953.

But on the streets of Seoul, where many were still mourning the suicide of former President Roh Moo-hyun, there was no palpable sense of fear in the hours after the North Korean nuclear test.

"I see this test as North Korea's marketing strategy. They just seem to be playing games," said Kim Sun-joo, 51, who works at a travel agency. "I wouldn't say that South Korea is completely free of danger, but I don't think we are any more in danger than we were before. People here are used to these kinds of threats."

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