North Korea's top diplomat said the country might test a hydrogen bomb over the Pacific Ocean in response to President Donald Trump's threat to ‘totally destroy’ North Korea. Photo: AP 
 
 SEOUL—North Korea’s foreign minister said the country could detonate a hydrogen bomb over the Pacific Ocean in response to President Donald Trump’s speech before the United Nations that warned the U.S. would annihilate North Korea if forced to defend itself or its allies. 
 
 The threat, made in remarks by North Korean Foreign Minister Ri Yong Ho in New York, would mark a dramatic escalation in action from Pyongyang, which in the past month has already launched two intermediate-range ballistic missiles over Japan and tested what... 

 SEOUL/TOKYO (Reuters) - Detonating a nuclear-tipped missile over the Pacific Ocean would be a logical final step by North Korea to prove the success of its weapons program but would be extremely provocative and carry huge risks, arms control experts said on Friday. 
 
 FILE PHOTO: North Korean leader Kim Jong Un watches the launch of a Hwasong-12 missile in this undated photo released by North Korea's Korean Central News Agency (KCNA) on September 16, 2017. KCNA via REUTERS 
 
 North Korean Foreign Minister Ri Yong Ho suggested leader Kim Jong Un was considering testing “an unprecedented scale hydrogen bomb” over the Pacific in response to U.S. President Donald Trump’s threat at the United Nations to “totally destroy” the country. 
 
 “It may mean North Korea will fire a warhead-tipped (intermediate range) Hwasong-12 or Hwasong-14 intercontinental ballistic missile and blow it up a few hundred kilometers above the Pacific Ocean,” said Yang Uk, a senior researcher at the Korea Defence and Security Forum in Seoul. 
 
 “They may be bluffing, but there is a need for them to test their combined missile-bomb capability. They could have already prepared the plan and are now trying to use Trump’s remarks as an excuse to make it happen,” said Yang. 
 
 Such an atmospheric test would be the first globally since China detonated a device in 1980, according to the International Atomic Energy Agency. 
 
 Tests of nuclear-tipped ballistic missiles are rarer still. The United States’ only test of an operational ballistic missile with a live warhead was fired from submarine far out in the Pacific Ocean in 1962. 
 
 China was widely condemned for a similar test with a missile that exploded over its Lop Nur test site in the country’s west in 1966. 
 
 North Korea’s six nuclear tests to date have all been underground, the most recent earlier this month by far its largest. 
 
 “We have to assume they *could* do it, but it is exceedingly provocative,” said Vipin Narang, an associate professor of political science at Massachusetts Institute of Technology. 
 
 “To put a live nuclear warhead on a missile that’s only been tested a handful of times, overflying potentially populated centers. If it...doesn’t go exactly as planned....it could be a world changing event.” 
 
 North Korea has fired two ballistic missiles over Japan’s north Hokkaido region in the past month as part of a series of tests that experts say have illustrated unexpectedly rapid advances. 
 
 “They said Pacific Ocean, which pretty much means firing a missile over Japan,” said Melissa Hanham, a senior research associate at the U.S.-based Middlebury Institute of International Studies at Monterey, California. “They want to shut us all up for doubting they could build it.” 
 
 SERIOUS FALLOUT 
 
 While a missile would be the most ideal means of delivery, it is also possible to put a bomb on a ship and detonate on the surface of the ocean or in the sea, the experts said. 
 
 Either way, the radioactive fallout could be significant, as well as the diplomatic backlash from around the world. North Korea’s recent missile launches over Japan especially drew stern rebukes from Tokyo and the international community. 
 
 Japan’s Chief Cabinet Secretary Yoshihide Suga called Pyongyang’s remarks and behavior “completely unacceptable”. 
 
 Narang said a test high enough over the ocean would limit the radioactive fallout but risks included damage from an electro-magnetic pulse, something Pyongyang has hinted it might employ on an attack on the United States or its allies. 
 
 “If it doesn’t go exactly as planned and the detonation occurs at a lower altitude we could see some EMP-like effects for anything in the area. A lot of dead fish too.” 
 
 Pyongyang has launched dozens of missiles this year as it spurs a program aimed at mastering a nuclear-tipped missile that can strike the United States, in addition to its Sept 3 nuclear test. 
 
 If Kim’s threat materializes, it will be a “tipping point” for China, and may prompt many other countries to demand an “end to the regime,” said David Albright, founder of the non-profit Institute for Science and International Security in Washington. 
 
 “No one has tested above ground for decades and the radioactive fallout could be terrifying to many,” Albright said. 
 
 Other experts said such an atmospheric nuclear test is unlikely for now due to its substantial technical and diplomatic risks. 
 
 Joshua Pollack, editor of the Washington-based Nonproliferation Review, said it would be an “end-to-end demo of everything.” 
 
 “But I would be surprised if this were their very next move. They have yet to test an ICBM at full range into the Pacific,” said Pollack. “That will probably come first.”
– Tensions between the US and North Korea continue to escalate. First the leader of the former threatened to wipe out the latter. Then Kim Jong Un followed up by calling Trump a "mentally deranged US dotard," and Trump capped that off with a new warning Friday, tweeting that Kim "will be tested like never before!" But the North this week also suggested a move that goes beyond words—and could lead to a "lot of dead fish": detonating a nuclear bomb a few hundred miles over the Pacific Ocean, per Reuters. North Korean Foreign Minister Ri Yong Ho dropped hints on a South Korean news channel (his own apparent musings, not official word from Kim) that the North may conduct "a historic aboveground test of a hydrogen bomb over the Pacific Ocean," per the Wall Street Journal. Yang Uk, a Korea Defense and Security Forum researcher, tells Reuters that North Korea "may be bluffing"—or seeking an excuse, like Trump's words, for a test. The last time a nation experimented with an atmospheric detonation was in 1980, when China did so. MIT professor Vipin Narang says such a move would be "provocative" and, if anything goes awry, a possibly "world-changing event." Radioactive fallout would be a danger—though Narang says it may not be so bad if the detonation took place high enough—as would the effects of electromagnetic pulses. A US missile analyst tells the Journal North Korea could also pack a hydrogen bomb on a ship and set it off in the sea. (Here's what "dotard" means.)