New York: North Korea on Friday conducted its fifth and biggest nuclear test and said it had mastered the ability to mount a warhead on a ballistic missile, prompting world powers to express outrage.
South Korea, the United States, Japan, Russia and China all condemned the blast at the Punggye-ri nuclear site, the North`s fifth and most powerful yet at 10 kilotons.
Under 32-year-old third-generation leader Kim Jong Un, North Korea has sped up development of its nuclear and missile programs, despite UN sanctions that were tightened in March and have further isolated the impoverished country.
The United States, meanwhile, called on China to put pressure on North Korea to denuclearise.
US Defense Secretary Ash Carter, on a visit to Norway, also reaffirmed an "iron-clad" commitment to defend South Korea and condemned the North Korean test as a direct challenge to the entire international community.
At the United Nations, Secretary-General Ban Ki-moon urged the Security Council to take "appropriate action" after what he called a "brazen breach" of the council`s resolutions.
"The patience on our side and that of the international community has already reached its limit," South Korean President Park Geun-Hye said, slamming the North`s young leader Kim Jong-Un for his "maniacal recklessness."
The news drew swift condemnation from US President Barack Obama, who called the test "a grave threat to regional security and to international peace and stability" and vowed to push for new international sanctions.
Japan condemned the test as "absolutely unacceptable," Russia expressed "extreme concern," and the head of the UN atomic watchdog said it was a "clear violation" of numerous Security Council resolutions.
"I count on the Security Council to remain united and take appropriate action. We must urgently break this accelerating spiral of escalation," Ban told reporters ahead of the Security Council talks called by the United States and Japan.
Obama said he had called the leaders of South Korea and Japan to confer over the crisis, with Park and Japanese leader Shinzo Abe also agreeing to cooperate closely with each other.
Pyongyang`s state media said the test, which comes after a series of ballistic missile launches, had realized the country`s goal of being able to fit a miniaturized warhead on a rocket.
"Our nuclear scientists staged a nuclear explosion test on a newly developed nuclear warhead at the country`s northern nuclear test site," a North Korean TV presenter said.
First indications of an underground explosion came when seismic monitors detected a 5.3-magnitude "artificial earthquake" near the Punggye-ri nuclear site.
"The 10-kiloton blast was nearly twice the (power of the) fourth nuclear test and slightly less than the Hiroshima bombing, which was measured about 15 kilotons," said Kim Nam-Wook of the South`s meteorological agency.
But attention soon shifted from the blast`s power to Pyongyang`s claim that it was a miniaturized warhead.
This week`s events pose yet another challenge for Pyongyang`s chief ally, China, which has been under pressure to rein in its increasingly aggressive neighbor.
Beijing said on Friday it "firmly opposes" the test, but it has limited room to maneuver. Its priority is to avoid the regime`s collapse, which would create a crisis on its border and shift the balance of power on the Korean peninsula toward the United States.
If Pyongyang can make a nuclear device small enough to fit on a rocket -- and bolster the range and accuracy of its missiles -- it might achieve its oft-stated aim of hitting US targets. But its past claims to have achieved that have been discounted.
However, North Koreans who gathered around public screens to watch the official announcement of the test -- which came on the 68th anniversary of the country`s founding -- were approving.
"US bastards may be saying this and that, but we fear nothing as our military power has strengthened further," said a woman who did not give her name.
Ordinary North Koreans usually express only officially sanctioned views when questioned by foreign news organizations.
Pyongyang routinely insists Washington is on the verge of launching an all-out war against it.
North Korea has been hit by five sets of United Nations sanctions since it first tested a nuclear device in 2006, but has insisted it will continue come what may.
The nuclear program has accompanied a series of ballistic missile launches, the latest of which took place on Monday as world powers gathered for a G20 meeting in China.
(With Agency inputs)
