North Korea Says It Successfully Tested First Hydrogen Bomb

(Bloomberg) -- North Korea said it tested its first hydrogen bomb, risking reigniting tensions with China and the U.S. after months of calm even as some experts cast doubt on the full extent of Pyongyang’s claim.

The reclusive regime tested the device at 10 a.m. local time, the official Korean Central News Agency said, and the blast triggered a magnitude 5.1 earthquake. But its claims to have detonated a hydrogen bomb -- rather than a less powerful atomic bomb -- immediately drew skepticism.

North Korea carried out the test “safely” and “perfectly” in an act of “self-defense” against its enemies, KCNA said. It “has confidently risen to the ranks of nuclear powers with hydrogen bombs by perfectly succeeding in the historic test of a hydrogen bomb,” Korean Central Television anchorwoman Ri Chun Hui said.

The detonation puts the erratic regime’s weapons program back on the global diplomatic agenda. If it proved to be a hydrogen weapon it would bring Kim Jong Un’snation into an elite league of nuclear powers as only a few nations are known to possess hydrogen bombs, including the U.S. and China.

It’s the second nuclear test since Kim came to power four years ago and began consolidating his grip through purges and provocations, rebuffing U.S. and Chinese efforts to restart disarmament talks on ice since 2009. The test drew condemnation from Japan, South Korea, Russia and the U.S., with Japan calling it a violation of United Nations Security Council resolutions. China, a longstanding ally, said volatility on the peninsula is “not in anyone’s interest.”

The Korean won declined as much as 0.8 percent to 1,197.85 per dollar, the weakest level since September. The Kospi index of shares fell as much as 1 percent, though makers of defense products like Speco Co. surged by up to 30 percent. The overall impact was muted as investors are used to North Korea’s bluster and prior tests didn’t lead to war, said Lee Seung Jun, managing director for active investment at Samsung Asset Management.

Kim has in the past used provocations to try and wring economic and political concessions from South Korea and the U.S. Still, the timing took some analysts by surprise: In a new year message only last week Kim pledged to “actively” work to improve ties with Seoul.

Nothing To Lose

“From a technical point of view, they need to do a fourth test as part of their ongoing nuclear program,” said John Delury, a historian at Yonsei University in Seoul. “What have they got to lose? There will be some hustle and bustle at the UN Security Council. There will be more sanctions, but they are already sanctioned to death.”

“From a domestic point of view, this is another way that Kim Jong Un asserts his power at home and his independence from Xi Jinping and China,” he said.

Doubt was also cast on North Korea’s claims to have tested a hydrogen device. Such a weapon can be hundreds or even thousands of times more powerful than an atomic bomb. An atomic bomb must be detonated to achieve the high temperatures required to set off the chain reaction that powers the hydrogen bomb.

South Korea’s spy agency said the test may not have been a hydrogen device, according to Lim Dae Sung, an aide to lawmaker Lee Cheol Woo who was briefed by the National Intelligence Service. The yield and the seismic wave from the quake triggered by the explosion were lower than the regime’s test in 2013, Lim said. Lee was unavailable to comment directly.

"From the data we know so far, it at most was a boosted atomic device, but not a hydrogen bomb," said Li Bin, a senior associate focused on nuclear policy at the Carnegie Endowment for International Peace.

North Korea’s claims of putting a satellite in orbit in 1998 and 2009 were disputed by South Korea and the U.S. It succeeded in putting a satellite in space in December 2012. Image experts have also accused North Korea of doctoring photos of military drills or floods before releasing them to the world.

Proof that North Korea has been able to develop a thermonuclear device would help Kim further emerge from the shadow of his father, Kim Jong Il, who died suddenly in December 2011 with little time to groom his son for the leadership. Kim is believed to be in his early 30s.

U.S. officials have previously said it was unlikely the regime could have developed a hydrogen bomb and have challenged its claims it was capable of miniaturizing a nuclear device to mount it on a missile. North Korea says its rockets can reach parts of the U.S.

Kim’s prior provocations have caused spikes in tension on the peninsula, followed by periods of relative calm. Frictions with South Korea rose in August to the highest level since 2013 -- sparked by South Korea’s resumption of propaganda broadcasts across the border after two soldiers were maimed by land mines - - but faded after the countries held talks.

‘Clear Breach’

Japan and South Korea condemned Kim’s latest action. “It is a clear breach of United Nations Security Council resolutions,” said Japanese Prime Minister Shinzo Abe. The UN council will meet later Wednesday, Reuters reported.

“We must gravely understand this situation and sternly respond with strong international sanctions against North Korea,” South Korean President Park Geun Hye said at a national security meeting in Seoul.

China "strongly opposes" North Korea’s tests and will summon its highest officials to register our "solemn representation," Foreign Ministry spokeswoman Hua Chunying said at a daily briefing in Beijing. “Any thoughts or action to disrupt the peace and stability of northeast Asia are not apt and not wise," the official Xinhua News Agency said in a separate commentary.

The detonation will be a test for China, said Ralph Cossa, president of the Pacific Forum CSIS in Honolulu.

How Tough

A visit by a high-ranking Chinese official to North Korea late last year raised the assumption of a “quid pro quo, that North Korea would be behaving themselves,” Cossa said. “The Chinese gotta feel somewhat embarrassed,” he said. “So the question now is how tough are the Chinese prepared to be.”

In a statement the U.S. said it could not confirm North Korea’s claims but condemned any violation of UN resolutions.

“We have consistently made clear that we will not accept it as a nuclear state,” National Security Council spokesman Ned Price said. “We will continue to protect and defend our allies in the region.”

--With assistance from Justina Lee, David Tweed, Isabel Reynolds, Ting Shi, Andy Sharp, Simon Lee, Heejin Kim and Clement Tan.

To contact the reporters on this story: Sam Kim in Seoul at skim609@bloomberg.net; Cynthia Kim in Seoul at ckim170@bloomberg.net To contact the editors responsible for this story: Rosalind Mathieson at rmathieson3@bloomberg.net; Andrew Davis at abdavis@bloomberg.net