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North Korea has conducted its fourth nuclear test, a setback for US and Chinese efforts to convince leader Kim Jong-un to restart disarmament talks.
White House sceptical of North Korean nuclear test
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White House sceptical of North Korean nuclear test
White House spokesman Josh Earnest says initial analysis of the test is "not consistent" with North Korea's claim it successfully detonated a hydrogen bomb, but that any kind of nuclear test is "provocative".
The regime in Pyongyang detonated a hydrogen device at the Punggye-ri underground test site in the far northeast, its official Korean Central News Agency said. The explosion was first detected as a magnitude 5.1 earthquake by the US Geological Survey.
The test is the second since Kim Jong-un became supreme leader and began consolidating power through a series of purges and provocations against South Korea. Mr Kim has rebuffed US and Chinese efforts to restart talks and has expanded the country's nuclear arsenal that he says is the best defense against a US invasion.
North Korea said on Wednesday it would continue to strengthen its nuclear program in order to protect itself against the hostile policies of the United States. It said the test was conducted "pursuant to the strategic determination of the Workers' Party of Korea".
In the statement, KCNA said North Korea would not not give up its nuclear program as long as the US maintained what it called "its stance of aggression".
North Korea had "fully proved that the technological specifications of the newly developed H-bomb for the purpose of test were accurate and scientifically verified the power of smaller H-bomb", the statement said.
It also said North Korea will act as a responsible nuclear state and vowed not to use its nuclear weapons unless its sovereignty was infringed. It also said it will not transfer its nuclear capabilities to other parties.
Full North Korea government statement on claimed hydrogen bomb test pic.twitter.com/fXW0irsTyw— Jon Passantino (@passantino) January 6, 2016
Last month, Mr Kim appeared to claim his country had developed a hydrogen bomb, also known as a thermonuclear device, a step up from the less powerful atomic bomb, but the United States and outside experts were sceptical at the time.
Some analysts questioned whether Wednesday's test was indeed of a hydrogen device.
South Korean intelligence officials and several analysts questioned whether Wednesday's explosion was indeed a full-fledged test of a hydrogen device.
The device had a yield of about six kilotonnes, according to the office of a South Korean lawmaker on the parliamentary intelligence committee – roughly the same size as the North's last test, which was equivalent to six to seven kilotonnes of TNT.
"North Korea has made claims about its nuclear and missile programs in the past that simply have not held up to investigation," said Melissa Hanham, a senior research associate at the California-based James Martin Center for Nonproliferation Studies.
Yang Uk, a senior research fellow at the Korea Defence and Security Forum, added: "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 US State Department said it condemned any violation of UN resolutions by North Korea.
North Korea announces nuclear test
North Korea announced on Wednesday that it has tested a nuclear device, after reports of a non-natural earthquake near a previously-used test site.
"While we cannot confirm these claims at this time, we condemn any violation of UNSC Resolutions and again call on North Korea to abide by its international obligations and commitments," White House National Security Council spokesman Ned Price said in a statement late.
Mr Price said the United States will continue to "protect and defend our allies in the region," and will "respond appropriately to any and all North Korean provocations."
British Foreign Secretary Philip Hammond said on Wednesday a test of a hydrogen nuclear bomb by North Korea would be a "provocation which I condemn without reservation".
Mr Hammond tweeted the statement during his two-day trip to Beijing: "If North Korean H-bomb test reports are true, it is a grave breach of #UNSC resolutions and a provocation which I condemn without reservation."
North Korea has been under UN Security Council sanctions due to its nuclear weapons program since it first tested an atomic device in 2006. It had conducted two other tests – in 2009 and 2013.
Japan said it would be in close contact with the governments of the US, South Korea, China and Russia over the issue, its top government spokesman said.
"This is something we can not accept, we strongly protest this," chief cabinet secretary Yoshihide Suga told a news conference.
Australian Foreign Affairs Minister Julie Bishop said North Korea's actions fly in the face of international non-proliferation norms.
"North Korea's ongoing development of nuclear weapons and ballistic missiles, and its proliferation of sensitive technologies, threaten the peace and security of Australia's friends and partners in our region and beyond," her office said in a statement.
"Today's nuclear test confirms North Korea's status as a rogue state and a continuing threat to international peace and security. We will intensify our counter-proliferation cooperation with partners to strengthen sanctions, aiming to reduce the funding of North Korea's WMD programs."
Australia would make its concerns known to the North Korean government directly, as well as in international and regional forums.
"Australia will continue to work with our friends and partners to support the security of the Republic of Korea and the stability of our region," the statement said.
France condemned the reported test, calling for a "strong reaction from the international community", President Francois Hollande's office said in a statement.
The United Nations Security Council planned to hold an emergency meeting on Wednesday to discuss the test, according to three council diplomats.
Speaking on condition of anonymity, the diplomats said the meeting would probably take place at 11am Wednesday New York time. One diplomat said it would likely be held behind closed doors.
Another council diplomat said the United States and Japan jointly requested the urgent council meeting.
It was not immediately clear what action, if any, the 15-nation council was planning to take in response to the test claims.