North Korea has launched five projectiles into the Sea of Japan, its latest military manoeuvre amid concerns about its nuclear programme. 
 
 South Korea disputed Pyongyang's description of the projectiles as "missiles" on Monday, saying instead the objects were smaller "short-range projectiles" - most likely conventional shells. 
 
 South Korean officials said the five projectiles flew about 200 kilometres after being launched from an area about 20km south of Hamhung on Monday afternoon local time. 
 
 Tensions have been soaring on the divided Korean peninsula since the North carried out its fourth nuclear test on January 6, followed a month later by a long-range rocket launch that was widely seen as a disguised ballistic missile test. 
 
 The UN Security Council responded earlier this month by imposing its toughest sanctions on North Korea to date. 
 
 In recent weeks Pyongyang has maintained a daily barrage of nuclear strike threats against both Seoul and Washington, ostensibly over continuing large-scale South Korea-US military drills that the North sees as provocative rehearsals for invasion. 
 
 Al Jazeera's Adrian Brown, reporting from Beijing, said Monday's tests follow the launch of ballistic missiles in the same area just a few days earlier. 
 
 "It's the timing of this that is so interesting, because on Friday North Korea said it carried out two ballistic missile tests roughly in the same area," he said. 
 
 "A few days before, the North Korean military warned that it was launching multiple ballistic missile launches and a nuclear warhead test," Brown said, adding that the tests were a "slap in the face of China", Pyongyang's closest ally. 
 
 US and South Korean intelligence assessments do not currently hold the North capable of launching missiles carrying a nuclear weapon. 
 
 Analyst BJ Kim from Hankuk University in Seoul told Al Jazeera that Pyongyang was "raising the stakes" with an eye on possible talks with Western powers. 
 
 "At this point from the North Korean perspective it makes perfect sense to look tough ... this is very predictable behaviour that we've been seeing," he said. 
 
 China concerns 
 
 Chinese Foreign Ministry spokeswoman Hua Chunying said China was "deeply concerned" about the situation on the Korean peninsula. 
 
 "We hope North Korea does not do anything to contravene UN Security Council resolutions," she said. 
 
 "We also hope all sides can remain calm and exercise restraint and avoid doing anything to exacerbate confrontation or tensions." 
 
 Speaking on China's ability to rein in the North, Kim said Pyongyang had become increasingly dismissive of the pressure Beijing could put on it. 
 
 "They [North Korea] are trying to show to the world that China doesn't have much leverage over them and that they're on their own," he said. ||||| 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.”
– Just in case anybody missed the three short-range missiles North Korea fired off into the sea yesterday, Pyongyang launched a fourth missile in the same area today, reports CNN. That flies in the face of Western calls to cool it already, notes Reuters, after UN chief Ban Ki-moon voiced concern, calling yesterday's launches a "provocative action." Saber-rattling or no, the region is still decidedly calmer than last month, a Seoul-based journalist says. "It's really simply because it's North Korea doing this that it raises concerns," he said. "The North Koreans have significantly de-escalated their bellicosity and their rhetoric since the end of April." Seoul, which confirmed the launch today, "will not be strongly condemnatory of this test because right now they are very, very keen to get the North Koreans to the negotiating table."