North Korea has confirmed it has carried out a third nuclear test after monitoring agencies reported an “unusual seismic event”.
“A third nuclear test has been successfully staged,” the North’s state-run Korean Central News agency said.
“The nuclear test was conducted as part of measures to protect our national security and sovereignty against the reckless hostility of the United States that violated our republic’s right for a peaceful satellite launch.”
A 4.9 magnitude earthquake was detected just north of a site where Pyongyang conducted nuclear tests in 2009.
The South Korean defence ministry, which raised its military alert level after the quake, said the blast had an explosive yield of between six and seven kilotons (6-7kt) and was of “enormous destructive power”.
In comparison, the nuclear weapons detonated above Hiroshima and Nagasaki in 1945 carried a yield of around 20kt each.
A spokesperson for the UN boss Ban Ki-moon said: “The Secretary-General condemns the underground nuclear weapon test conducted by the Democratic People’s Republic of Korea today.
“It is a clear and grave violation of the relevant Security Council resolutions.”
Tibor Toth, the executive secretary of the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organisation (CTBTO), said the event’s location was “roughly congruent with” nuclear tests carried out by North Korea in 2006 and 2009.
“This act would constitute a clear threat to international peace and security, and challenge efforts made to strengthen global nuclear disarmament and non-proliferation, in particular by ending nuclear testing,” he added.
China expressed its “firm opposition” to North Korea’s nuclear test, saying its wayward ally had gone ahead with the blast “despite widespread opposition from the international community”.
“We strongly urge the DPRK to honour its commitment to denuclearisation, and not to take any actions which might worsen the situation,” the foreign ministry said in a statement posted on its website.
The UN Security Council will hold urgent talks on the blast at 2pm GMT and US President Barack Obama said the test posed a threat to international peace and security.
The Foreign and Commonwealth Office said: “The UK will begin urgent consultations with Security Council partners calling for a robust response to this latest development.”
Mr Obama said the US will “continue to take steps necessary to defend ourselves and our allies” and it will work with other nations “to pursue firm action”.
He added that North Korea’s action “warrants further swift and credible action by the international community”.
Foreign Secretary William Hague said: “North Korea’s development of its nuclear and ballistic missile capabilities poses a threat to international and regional security.
“Its repeated provocations only serve to increase regional tension, and hinder the prospects for lasting peace on the Korean peninsula.”
Japan said the North Korean nuclear test was a “grave threat”, according to Prime Minister Shinzo Abe.
“(The test) is a grave threat to the safety of our country and a serious challenge against the global framework of nuclear disarmament and non-proliferation,” Mr Abe said in a statement, adding it “cannot be tolerated”.
After the blast took place a North Korean newsreader urged the Korean People’s Army (KPA) to prepare for combat against its foes.
She stressed that If an order was given “the KPA should blow up the stronghold of aggression at a strike”.
“And wipe out the brigandish US imperialists and South Korea puppet army to the last man and thus accomplish the historic cause of national reunification.”
