Experts cast doubt on claim, saying evidence points to test involving uranium or plutonium device, while UN security council will discuss possible sanctions 
 
 North Korea has conducted its fourth nuclear test, the country’s state media has announced, in a move that could take it a step closer to developing nuclear warheads capable of striking the US mainland. 
 
 
 
 Some experts, though, said initial evidence was pointing towards a test involving a uranium or plutonium device and not, as Pyongyang has claimed, a far more powerful hydrogen bomb. 
 
 North Korea to make 'major announcement' following artificial earthquake near nuclear test site – live Read more 
 
 An announcement on North Korean television said the country had successfully tested a “miniaturised hydrogen bomb” underground on Wednesday morning, describing it as an “act of self-defence” against the US. North Korean claims about the size and type of bomb have not been independently verified. 
 
 If the claims are true, it would be the first time the North has successfully tested a hydrogen bomb and could also enable the secretive state to launch long-range nuclear missiles. 
 
 “If it’s true, it means they’ve made something smaller scale, capable of being put onto a missile, said John Carlson, the former head of the Australian Safeguards and Non-Proliferation Office. “I think we can assume the previous tests they’ve carried out have been devices too large to fit onto a missile.” 
 
 South Korea’s spy agency believes the seismic wave reported was more likely caused by an atomic bomb, Lee Cheol Woo, a South Korean politician, said. 
 
 Yang Uk, a senior research fellow at the Korea Defence and Security Forum, said: “Given the scale it is hard to believe this is a real hydrogen bomb. They could have tested some middle stage kind (of device) between an A-bomb and H-bomb, but unless they come up with any clear evidence, it is difficult to trust their claim.” 
 
 The North Korean state television broadcast said the test was a “complete success” which propelled the country into the “rank of advanced nuclear states”. It had been overseen by the country’s leader, Kim Jong-un and conducted ahead of his 33rd birthday this Friday. 
 
 
 
 “[North Korea’s] fate must not be protected by any forces, only by [North Korea] itself,” the broadcast said. North Korea would not abandon its nuclear weapons program as long as the US maintained what it called “its stance of aggression”. 
 
 “The US has gathered forces hostile to DPRK [Democratic People’s Republic of Korea] and raised a slanderous human rights issue to hinder DPRK’s improvement,” it said. 
 
 “It is just to have H-bomb as self-defence against the US having numerous and humongous nuclear weapons. The DPRK’s fate must not be protected by any forces but DPRK itself.” 
 
 The United Nations security council was planning to meet on Wednesday morning in New York to discuss North Korea’s nuclear test, council diplomats said. 
 
 The White House said it could not confirm North Korea’s claims, but added the United States would respond appropriately to provocations and defend its allies. The EU said the test was a “grave violation” of UN resolutions. 
 
 Phillip Hammond, the British foreign secretary, said on a visit to Beijing: “I think I can say that Britain and China are pretty much completely aligned on North Korean nuclear. We both strongly oppose the acquisition or testing of nuclear weapons by North Korea and we both want to see a resumption of the six party talks. 
 
 “So far as I think any of us can tell, there is no reason to doubt what the North Koreans are claiming – that they have carried out a test detonation of an H bomb. It is clearly very bad news for the non-proliferation agenda generally and for security in the region specifically.” 
 
 South Korean president Park Geun-hye said the country would take decisive measures against any additional provocations by North Korea and work with the international community to make sure the country pays the price for its latest nuclear test. 
 
 Park said the latest test could change the fundamental nature of the situation over North Korea’s nuclear programme. 
 
 Prime minister Shinzo Abe said Japan would make a firm response to North Korea’s challenge against nuclear non-proliferation, calling its test a threat to Japan’s security. 
 
 
 
 The test is bound to ratchet up tensions between the isolated country and its neighbours as well as Washington. China’s foreign ministry said that Beijing did not have advance knowledge of the test and added that it firmly opposes Pyongyang’s action. 
 
 
 
 North Korea conducted nuclear tests in 2006, 2009 and 2013, drawing condemnation and rounds of UN sanctions banning trade and financing activities that aid its weapons program. 
 
 
 
 A successful fourth test could deepen North Korea’s international isolation if the UN security council decided to respond with more sanctions. Pyongyang is thought to have developed several crude nuclear weapons. 
 
 Timeline: North Korea’s nuclear weapons development Read more 
 
 Since becoming North Korean leader in late 2011, Kim Jong-un has stepped up condemnation of joint US-South Korean military drills he believes are preparation for an invasion. 
 
 
 
 In early 2013, Kim responded to UN sanctions imposed after North Korea’s third nuclear test by unleashing a barrage of threats aimed at South Korea, the US and Japan. 
 
 Kim appears to have caught the world off-guard yet again. He did not mention his country’s pursuit of a nuclear deterrent in his New Year’s address, an omission some analysts say was designed to improve the prospects of a summit with the Chinese leader, Xi Jinping. 
 
 Last month Washington dismissed Kim’s claims that his country had developed a hydrogen bomb – a development that, if true, would mark significant progress in North Korea’s nuclear capability. Hydrogen bombs are capable of producing a far more powerful blast than basic atom bombs. 
 
 An intensity shake map released by the US Geological Survey on 5 January shows the location where a preliminary 5.1 magnitude earthquake struck in North Korea. Photograph: US Geological Survey/EPA 
 
 John Carlson said the veracity of North Korea’s claim would be difficult to determine “until we can analyse any gases emitted, and it could take several days for those to show up, if it all”. 
 
 He said it would be a “major challenge” for the North Korean regime to develop a thermonuclear weapon, particularly a miniaturised version, which required even greater expertise. 
 
 “Their claim would be far more convincing if it was a larger size,” he said. 
 
 Carlson, who headed Australia’s safeguards office for more than two decades, said it was possible Pyongyang had actually produced a lower-yield “boosted explosion”, in which the hydrogen isotope tritium undergoes partial fusion, allowing them to describe the device as a hydrogen bomb. 
 
 “I think it’s feasible that they’ve done that and they’re claiming that they’ve done more,” he said. 
 
 Speculation that the regime in Pyongyang had conducted a surprise nuclear test on Wednesday rose after seismologists from South Korea, China and other countries said they had detected a “manmade” earthquake in the country that could have been caused by an explosion. 
 
 
 
 South Korean meteorological officials said the epicentre of the quake was 49km (30 miles) from the Punggye-ri site in North Hamgyong province, where North Korea has conducted nuclear tests in the past. 
 
 How to stop worrying and embrace a nuclear North Korea Read more 
 
 Yonhap news agency in South Korea said North Korea had not given notice of the test, which was carried out at 10am local time (1am GMT), to the US or its traditional ally China. 
 
 Wednesday’s tremor was a “suspected explosion”, the China earthquake network centre said on its website. It gave the magnitude as 4.9. 
 
 The US Geological Service said it had detected a 5.1 magnitude quake, and the European Mediterranean seismological centre said it had also detected unusual seismic activity in North Korea. 
 
 “We suspect a manmade earthquake and are analysing the scale and epicentre of the quake with the geoscience and mineral resource institute of South Korea,” a Korea meteorological administration official said in the South Korean capital, Seoul. ||||| North Korea says it successfully tested a hydrogen nuclear bomb, a development that, if true, represents a dramatic advance in its military capabilities. Previously, the nation has tested plutonium weapons in three underground nuclear tests, but hydrogen bombs are much more powerful. 
 
 
 
 Around 10 a.m. local time on Wednesday, an earthquake was detected near North Korea's nuclear test site, sparking concern that the nation had conducted a fourth nuclear test. A short time later, a statement was read on North Korean state TV claiming that the nation detonated a "miniaturized" hydrogen nuclear bomb, and the test was a "perfect success." "If there's no invasion on our sovereignty we will not use nuclear weapon," the statement said. "This H-bomb test brings us to a higher level of nuclear power." 
 
 Statements from North Korea are notoriously untrustworthy — last summer the nation claimed to have invented a vaccine for Ebola, HIV, and "a number of cancers" — but obviously this is a concerning development. Here's what we know so far. 
 
 Did North Korea actually test a hydrogen bomb? 
 
 It seems highly likely that North Korea conducted some kind of nuclear test, but no one has independently verified that the weapon tested was in fact a hydrogen bomb — or, as North Korea described it, an "H-bomb of justice." And, experts are massively doubtful about the whole thing. 
 
 Or, as White House spokesperson Josh Earnest put it on Wednesday afternoon, there is “significant and understandable skepticism of the claims of the North Korean regime.” 
 
 The U.S. Geological Survey measured Wednesday morning's seismic activity, which took place northeast of Sungjibaegam, at a magnitude of 5.1, and South Korean experts said it appeared the quake was caused by a man-made explosion. A 4.9-magnitude earthquake was recorded near the same spot before North Korea confirmed its last nuclear test in 2013. 
 
 #NEWSGRAPHIC Map locating a quake in North Korea near its nuclear test site pic.twitter.com/q4WgE0v0H8 — Agence France-Presse (@AFP) January 6, 2016 
 
 People were evacuated from buildings after tremors from the explosion were felt in the Chinese border town of Yanji: 
 
 Picture shows students evacuated in Yanji near China-#DPRK border after Pyongyang's H-bomb test pic.twitter.com/kmSGvV5MJ9 — CCTVNEWS (@cctvnews) January 6, 2016 
 
 Recent satellite photos analyzed by 38 North, a Washington research institute that follows North Korea’s nuclear activity, showed evidence that the nation has been digging a new tunnel at its nuclear test site. Jeffrey Lewis, a nuclear expert at the Middlebury Institute of International Studies in Monterey, California, said last month that the tunnel made it “more likely that they will conduct a test in the coming year.” But he told the Washington Post that Wednesday’s blast wasn’t drastically bigger than in previous tests, suggesting it wasn’t a hydrogen bomb. 
 
 
 
 The South Korean defense ministry said it can't confirm what kind of event occurred, and a senior U.S. administration official told CNN that it may take days to obtain scientific data that can determine whether the test was successful. 
 
 South Korean lawmaker Lee Cheol Woo told the AP that he was told that the seismic wave caused by the test was small enough that people were skeptical that it could have been caused by even a failed hydrogen-bomb test. 
 
 For what it's worth, here's the announcement that aired on North Korean TV: 
 
 Why is this different from North Korea’s previous weapons tests? 
 
 In the past, North Korea has only tested bombs that use fission to break the atomic nucleus of elements like plutonium, releasing large amounts of energy. A thermonuclear bomb uses fusion to combine small atoms, such as hydrogen, creating a much larger blast. A fission weapon typically yields around ten kilotons, while a fusion weapon is measured in megatons (1,000 kilotons). If North Korea has a true hydrogen weapon, it would be hundreds of times more powerful than the bombs dropped on Hiroshima and Nagasaki. 
 
 North Korea’s development of a hydrogen bomb is also concerning because fusion weapons are much harder to make. Some experts believe Pyongyang may already have 10 to 15 atomic weapons, but the bombs are rudimentary. In May, it claimed to have developed miniaturized nuclear weapons, which could be delivered via missile, but many were skeptical. As the Associated Press notes, a successful test of a hydrogen bomb would mean that North Korean engineers are much closer to their stated goal of creating a stockpile of nuclear-tipped missiles that can reach the U.S. 
 
 North Korean leader Kim Jong-un claimed last month that his scientists were developing a hydrogen weapon, but Bruce Bennett, a senior defense analyst at the nonprofit Rand Corp., suggests that he may only have "boosted" weapons. As Bennett explains in a CNN opinion piece, that’s a far more plausible possibility, considering that North Korea only conducted its first nuclear test in 2006: 
 
 En route to the development of fusion weapons, some countries develop so-called "boosted" weapons, which use a small amount of fusion to boost the fission process, causing more large atoms to fission and thus releasing more energy — initially, perhaps a weapon of 50 kilotons or so. Because some fusion is involved in such a weapon, Kim may be claiming that he has achieved a hydrogen bomb when in practice he only has a boosted weapon. 
 
 
 
 What difference would a boosted nuclear weapon make? If North Korea really has a boosted nuclear weapon of perhaps 50 kilotons, it could do significant damage in a city as densely populated as Seoul, South Korea: About 250,000 people could be killed in such a strike, or about 2.5% of the population. This would mark a genuine advance in the level of damage that North Korea is capable of doing. And if North Korea one day produces a true hydrogen bomb of, say, one megaton yield, then it would be deadlier still. 
 
 Bennett added to the BBC, "The bang they should have gotten would have been 10 times greater than what they're claiming. So Kim Jong-un is either lying, saying they did a hydrogen test when they didn't, they just used a little bit more efficient fission weapon — or the hydrogen part of the test really didn't work very well or the fission part didn't work very well." 
 
 How are other nations responding? 
 
 The South Korean government convened an emergency meeting of its National Security Council. "This is a grave provocation to our security, threatening the survival and future of our nation and further directly challenging peace and stability in the world," said South Korean president Park Geun-hye. "The government — in close cooperation with the international community — should have North Korea pay a price without fail for the latest nuclear test." 
 
 Regardless of whether North Korea tested an H-bomb or conducted a smaller nuclear test, the world is very mad at Kim Jong-un. 
 
 Several other nearby nations held emergency meetings as well, and Japanese prime minister Shinzō Abe issued a statement condemning the test. "The nuclear test that was carried out by North Korea is a serious threat to the safety of our nation and we absolutely cannot tolerate this," he said. "This clearly violates U.N. Security Council resolutions and is a grave challenge against international efforts for non-proliferation.” 
 
 Although China is an ally, they were also not impressed by North Korea's bragging — and were not warned about the test in advance. A spokesperson at the Chinese Ministry of Foreign Affairs told reporters, “China is strongly against this act.” North Korea's only friend is probably getting pretty incensed at this point. As The Guardian points out, "Kim has refused to rejoin the Chinese-led six-party nuclear talks. In September, he snubbed President Xi Jinping’s invitation to attend celebrations marking the end of the second world war." 
 
 The New York Times adds that it was never surprising that North Korea was far less interested in taking part in international nuclear agreements than Iran: 
 
 From Pyongyang’s viewpoint, there is little incentive to give up the nuclear arsenal. The world is not exactly banging on North Korea’s door to do business the way it wants to resume relations with Iran: The North has no oil, no striving middle class, and little strategic value in the modern world. Its greatest power is the threat it poses to one of the most prosperous corners of the globe. 
 
 One analyst at the New Zealand Contemporary China Research Centre at the Victoria University of Wellington told the Washington Post, “In a way, this is a protest against Beijing. They are saying: ‘we can do whatever we want. This shows our independence and we don’t need your approval.’” 
 
 Russia wants everyone to chill out for a minute, in case North Korea didn't actually test a hydrogen bomb. The foreign ministry called on "all interested sides to preserve maximum restraint and to not take actions that could rouse the uncontrolled growth of tensions in Northeast Asia," per the AP. 
 
 The United Nations Security Council said it would meet on Wednesday, at the request of Japan and the United States. The 15-nation council put North Korea under sanctions after its first nuclear test, and if a fourth nuclear test is confirmed it's likely the penalties will be increased. 
 
 The White House National Security Council released this statement: 
 
 We are aware of seismic activity on the Korean Peninsula & have seen claims of a nuclear test. Statement: pic.twitter.com/WvyFkpJcZo — WH National Security (@NSCPress) January 6, 2016 
 
 State Department spokesperson John Kirby added, according to the Washington Post, “We have consistently made clear that we will not accept it as a nuclear state. We will continue to protect and defend our allies in the region, including [South] Korea, and will respond appropriately to any and all North Korean provocations.” 
 
 Marco Rubio was the first GOP presidential candidate to weigh in, offering this predictable assessment: 
 
 who has been expanding his nuclear arsenal while President Obama has stood idly by. (2/5) — Marco Rubio (@marcorubio) January 6, 2016 
 
 If this test is confirmed, it will be just the latest example of the failed Obama-Clinton foreign policy. (3/5) — Marco Rubio (@marcorubio) January 6, 2016 
 
 Senator Ted Cruz also blamed Obama and Hillary Clinton for the nuclear test, and then drew his own conclusions for what this all meant for Iran. "We saw last night the consequences of this deal if it is allowed to go forward," he said, according to the Washington Post. "[Iran's] nuclear test may not be underground, measured by an earthquake. It may be above the skies of Tel Aviv, or New York, or Los Angeles." 
 
 Donald Trump later added that North Korea was a problem that China should deal with. He also offered his analysis of Kim Jong-un, calling him a "madman." 
 
 "And nobody talks to him, other than of course Dennis Rodman. That's about it." 
 
 Hillary Clinton responded to the incident by drawing eyes back to her résumé. "As secretary, I championed the United States' pivot to the Asia Pacific — including shifting additional military assets to the theater — in part to confront threats like North Korea and to support our allies," she said in a statement. 
 
 Why would North Korea conduct a test now? 
 
 Sussing out Kim’s motives is nearly impossible, but we do have some clues about the timing. Friday is the leader’s 33rd birthday, and new nuclear capabilities are the perfect gift for a dictator. It’s also possible that Kim wants a major accomplishment to brag about in May, when the Korean Workers’ Party holds its first Communist Party congress in 36 years. 
 
 Phil Robertson at Human Rights Watch thought these were lousy reasons to conduct a test.“Kim Jong-un may think it appropriate to celebrate his birthday early with a nuclear test, but even a hydrogen bomb should not cause the world to forget that the Kim family’s hereditary dictatorship is built on the systematic brutalization and abuse of the North Korean people,” he said in a statement. 
 
 Kim may also be anxious about North Korea’s shaky ties to China, its last major ally, though the move is likely to worsen their relationship even further. Spokesperson Hua Chunying said China “firmly opposes” the purported hydrogen-bomb test, adding, ”North Korea should stop taking any actions which would worsen the situation on the Korean peninsula.” 
 
 North Korea offered a poetic explanation for its latest act of defiance. The televised statement said that for North Korea to give up its nuclear weapons program while the U.S. continues its "hostile policy" would be "as foolish as for a hunter to lay down his rifle while a ferocious wolf is charging at him." According to Shanghaiist, the state media agency, KCNA, added that any nuclear weapons tested were "self-defense against the US having numerous and humongous nuclear weapons." 
 
 KCNA also noted that "The U.S. is a gang of cruel robbers which has worked hard to bring even a nuclear disaster to the DPRK, not content with having imposed the thrice-cursed and unheard-of political isolation, economic blockade and military pressure on it for the mere reason that it has differing ideology and social system and refuses to yield to the former's ambition for aggression." 
 
 The L.A. Times talked to Bonnie Glaser at the Center for Strategic and International Studies, who "recalled one official saying that U.S. bargaining in the past had taught Pyongyang that it was 'OK to pee on the rug' and what was necessary now was to not get hysterical every time they 'engage in bad behavior' by going back with a fresh package of proposals." 
 
 Regardless of what the next year brings — does the U.S. try to talk it out with Kim? — it seems clear that North Korea has invited the world to invent new ways to sanction it, which will give the country plenty more reasons to hate the rest of the world. 
 
 This post has been updated throughout. ||||| There’s skepticism among nuclear experts and governments about North Korea’s claim Wednesday that it has successfully detonated its first hydrogen bomb, with the White House saying its initial analysis was “not consistent” with Pyongyang’s announcement. 
 
 “The initial analysis that has been conducted of the events that were reported overnight is not consistent with North Korean claims of a successful hydrogen bomb test,” Josh Earnest, the White House spokesman, said. “There’s nothing that’s occurred in the last 24 hours that has caused the United States government to change our assessment of North Korea’s technical and military capabilities.” 
 
 Nuclear and regional experts were also skeptical. 
 
 *IF* yield is c. 10 kT, seems unlikely to be true 2-stage thermonuclear bomb. Maybe a small boosted primary? Or a vanilla fission device? — James Acton (@james_acton32) January 6, 2016 
 
 Helpful North Korea context from Denny Roy, of the East-West Center: pic.twitter.com/b6bvKsTfMM — Adrienne LaFrance (@AdrienneLaF) January 6, 2016 
 
 Carl Bildt, the former Swedish prime minister, tweeted: 
 
 Very serious provocation by North Korea, although it's unlikely to have been a fully-fledged fusion bomb.https://t.co/8eHHQrSNzN — Carl Bildt (@carlbildt) January 6, 2016 
 
 The Arms Control Association in Washington pointed out that early readings “suggest a relatively low-yield underground nuclear test was conducted.” And, it added: 
 
 Determining what kind of fissile material was used for the bomb will be a challenge even if the radioactive gases produced by the test are once again detected by remote monitoring systems and airborne detection systems — a process that can take several days or even weeks as noble gases produced by the explosion seep up from the ground into the atmosphere. 
 
 The U.S. Geological Survey recorded a 5.1-magnitude seismic event about 11 miles from the North Korean town of Sunjibaegam in the country’s northwest. Tremors of a similar magnitude followed each of North Korea’s three previous nuclear-weapons tests— in 2006, with which it became the eighth declared nuclear-weapons state; 2009, and 2013— all of which occurred underground at the nearby Punggye-ri Nuclear Test Site. Experts pointed out that the magnitude of the tremors should have been far greater had Wednesday’s test been of a hydrogen bomb, which is far more powerful than the atomic bombs North Korea tested on the three previous occasions. 
 
 Atomic bombs rely on nuclear fission to achieve their destructive purpose. Like a dropped water balloon hitting a sidewalk, atomic bombs crack open the dense atomic nuclei of large, unwieldy elements like uranium and plutonium to release tremendous amounts of energy. 
 
 Hydrogen bombs, by contrast, use nuclear fission only for their initial detonation, igniting a secondary fusion stage by compressing lighter atoms of deuterium and tritium together until they explode, like filling up a water balloon until it bursts. The chain reaction produces a far more powerful explosion than an atomic bomb. ||||| The White House on Wednesday disputed North Korea’s claim that it carried out its first-ever test of a hydrogen bomb, which would be the most powerful weapon in the rogue state’s arsenal. 
 
 President Obama’s top spokesman, Josh Earnest, said initial analysis of the nuclear test by the U.S. and international bodies “is not consistent with North Korean claims of a successful hydrogen bomb test.” 
 
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 The statement came soon after the United Nations Security Council condemned the test and agreed to draft “significant measures” to punish Pyongyang. 
 
 Intelligence agencies are continuing to gather evidence to determine the nature of the incident, Earnest said, and a formal determination may not come for weeks. 
 
 But analysts said seismic readings of the explosion were smaller than expected from a hydrogen bomb detonation. The magnitude-5.1 tremor felt after the test was the same as the one felt in February 2013, when North Korea set off a less-powerful plutonium weapon. 
 
 The swift response underscored growing international concerns about North Korea’s desire to advance its nuclear capabilities, a development that could destabilize the tense Korean peninsula. 
 
 “Regardless of how successful the test is ... they have now done four tests and they know a lot about nuclear weapons,” said Jeffrey Lewis, a nonproliferation expert at the Middlebury Institute of International Studies at Monterey. “The bigger takeaway is that they’re going further down this path and that makes it harder to stop.” 
 
 Hydrogen bombs, also known as thermonuclear weapons, split atoms apart before slamming them together, in a process called fusion. The two-step process releases vastly larger amounts of energy, resulting in a much more powerful weapon than the ones dropped by the U.S. during World War II. 
 
 Pyongyang’s traditional adversaries, South Korea and Japan, joined the United States in denouncing the test. Obama was expected to phone Japanese Prime Minister Shinzo Abe and South Korean President Park Geun-hye Wednesday to further coordinate the global response. 
 
 Deputy Secretary of State Tony Blinken is heading to Asia next week, the State Department said — an already scheduled visit that will likely be consumed by the North Korean test. 
 
 During a national security meeting in Seoul, Park called the test a “grave provocation” that threatens the “survival and future of our nation.” 
 
 “The government — in close cooperation with the international community — should have North Korea pay a price without fail for the latest nuclear test,” she said. 
 
 Condemnation from China, North Korea’s closest ally, was significant. Beijing has been able to influence the country’s behavior, and U.S. officials are hoping it could send a message to North Korean leader Kim Jong Un, who has so far resisted international calls to abandon his nation’s nuclear program. 
 
 U.S. national security adviser Susan Rice met with China’s ambassador to the U.S., Cui Tiankai, at the White House on Wednesday to discuss the situation, Earnest said. 
 
 While it’s nearly impossible to determine the secretive Kim’s motives, the test comes just ahead of his 33rd birthday, on Friday. 
 
 This spring, the country is scheduled to hold its first Communist Party congress in almost four decades. Some ­observers suggested Kim could be trying to consolidate domestic support or extract concessions from China or the West. 
 
 “What is true is that North Korea continues to be one of the most isolated nations in the world, and their isolation has only deepened as they have sought to engage in increasingly provocative acts,” Earnest said. 
 
 “There is only one path out of the extreme poverty and isolation that they currently face,” he added. “And it’s not a path that is advanced by pursuing nuclear weapons.” 
 
 Pyongyang’s assertiveness illustrates Obama’s inability to restrain North Korea throughout his seven years in office, even as he trumpets success with brokering a nuclear deal with Iran. 
 
 North Korea has conducted three nuclear tests since 2006, all of which have been condemned by the international community. And diplomatic pressure and sanctions have done little to curb its nuclear ambitions. 
 
 “The administration’s North Korea policy is not successful,” said Daryl Kimball, executive director of the Arms Control Association. “They made a limited effort at engagement in 2012, it didn’t work out for them ... and then they go with maligned neglect.” 
 
 The test sparked a debate in the 2016 presidential campaign over which candidate is best equipped to respond to boisterous adversaries like North Korea. 
 
 Republican critics of Obama were quick to lay blame for the test at the administration’s door. 
 
 “Our enemies around the world are taking advantage of Obama’s weakness,” Sen. Marco Rubio (R-Fla.) said in a statement. “If this test is confirmed, it will be just the latest example of the failed Obama-Clinton foreign policy.” 
 
 Former Secretary of State Hillary Clinton, the Democratic front-runner, brushed aside that criticism and used the incident to bolster her national security bona fides. She called for stepped-up sanctions on Pyongyang. 
 
 “Threats like this are yet another reminder of what’s at stake in this election,” she said in a statement. “We cannot afford reckless, imprudent publicity stunts that risk war. We need a commander-in-chief with the experience and judgment to deal with a dangerous North Korea on day one.” 
 
 Julian Hattem and Kristina Wong contributed. 
 
 Updated at 8:30 p.m.
– A tense 2016 lies ahead on the Korean Peninsula after a North Korean nuclear test that could mark an alarming leap forward in the country's technology. Pyongyang claims that it successfully detonated a hydrogen bomb for the first time, though experts say the Wednesday morning explosion— believed to have caused a 5.1-magnitude quake—was closer in size to North Korea's three previous nuclear tests than to a hydrogen bomb explosion, reports the Washington Post. Kim Jong Un claimed last month that the country had an H-bomb, a weapon much more powerful and harder to make than an atomic bomb, and a confirmed test would almost certainly lead to tough new sanctions against North Korea, the AP reports. North Korean state media reported that the test of the "miniaturized" H-bomb was a "perfect success." It could be weeks before an H-bomb test can be confirmed by outside experts, who seem skeptical of Pyongyang's claims. "Given the scale, it is hard to believe this is a real hydrogen bomb," a rep from the Korea Defense and Security Forum tells Reuters. "They could have tested some middle stage kind [of device] between an A-bomb and H-bomb, but unless they come up with any clear evidence, it is difficult to trust their claim." The Australian Broadcasting Corporation reports that the United Nations Security Council plans to hold an emergency meeting Wednesday to discuss the nuclear test. (At the start of 2016, Kim said he was ready for war.)