North Korea conducted its fifth and biggest nuclear test on Friday and said it had mastered the ability to mount a warhead on a ballistic missile, ratcheting up a threat that its rivals and the United Nations have been powerless to contain.
The blast, on the 68th anniversary of North Korea’s founding, was more powerful than the bomb dropped on Hiroshima, according to some estimates, and drew condemnation from the United States as well as China, Pyongyang’s main ally.
Diplomats said the United Nations Security Council would discuss the test at a closed-door meeting on Friday, at the request of the United States, Japan and South Korea.
Kim Jong Un, North Korea leader, has accelerated the development of its nuclear and missile programmes, despite U.N. sanctions that were tightened in March and have further isolated the impoverished country.
South Korean President Park Geun-hye, in Laos after a summit of Asian leaders, said Kim was showing “maniacal recklessness” in completely ignoring the world’s call to abandon his pursuit of nuclear weapons.
U.S. President Barack Obama, aboard Air Force One on his way home from Laos, said the test would be met with “serious consequences”, and held talks with Park and with Japanese Prime Minister Shinzo Abe, the White House said.
China said it was resolutely opposed to the test and urged Pyongyang to stop taking any actions that would worsen the situation. It said it would lodge a protest with the North Korean embassy in Beijing.
There were further robust condemnations from Russia, the European Union, NATO, Germany and Britain.
North Korea, which labels the South and the United States as its main enemies, said its “scientists and technicians carried out a nuclear explosion test for the judgment of the power of a nuclear warhead,” according to its official KCNA news agency.
It said the test proved North Korea was capable of mounting a nuclear warhead on a medium-range ballistic missile, which it last tested on Monday when Obama and other world leaders were gathered in China for a G20 summit.
Pyongyang’s claims of being able to miniaturise a nuclear warhead have never been independently verified.
Its continued testing in defiance of sanctions presents a challenge to Obama in the final months of his presidency and could become a factor in the U.S. presidential election in November, and a headache to be inherited by whoever wins.
“Sanctions have already been imposed on almost everything possible, so the policy is at an impasse,” said Tadashi Kimiya, a University of Tokyo professor specialising in Korean issues.
“In reality, the means by which the United States, South Korea and Japan can put pressure on North Korea have reached their limits,” he said.