North Korea conducted its third nuclear test on Tuesday in defiance of United Nations resolutions, a move that angered the United States and Japan, infuriated its only major ally, China, and looks likely to increase United Nations sanctions against Pyongyang.
The North said the test had "greater explosive force" than the 2006 and 2009 tests that were widely seen as small-scale. Its KCNA news agency said it had used a "miniaturized" and lighter nuclear device, indicating that it had again used plutonium which is more suitable for use as a missile warhead. The US Geological Survey registered seismic activity measuring 4.9 magnitude in the area at the time of the test.
North Korean leader Kim Jong-un, the third of his line to rule the country, has now presided over two long-range rocket launches and a nuclear test during his first a year in power, pushing policies that have propelled his impoverished and malnourished country ever closer to becoming a nuclear weapons power.
US President Barack Obama said the test was a "highly provocative act" that hurt stability in the region and called its nuclear program a threat to U.S. and international security. China also strongly criticized the test, urging its ally to abide by its non-nuclear commitment and not take any actions that would worsen the situation on the Korean peninsula.
UN Secretary-General Ban Ki-moon condemned the test as "deplorable", and UN diplomats said the Security Council had scheduled an emergency meeting to discuss the possibility of imposing new sanctions on Pyongyang.
Russia's Defense Ministry said the power of the nuclear test blast Tuesday surpassed 7 kilotons, a ministry source told the Interfax-AVN military news agency.
South Korea said earlier on Tuesday that the size of the seismic activity indicated a nuclear explosion slightly larger than the North's two previous tests at 6-7 kilotons. The Hiroshima bomb was, by comparison, around 20 kilotons.
South Korea's UN mission said it called an emergency meeting of the 15-nation Security Council at 9 am EST (1400 GMT) on Tuesday to discuss the nuclear test. It added that South Korean Foreign Minister Kim Sung-hwan would address the media in New York after the meeting.
South Korea is the president of the council this month, which gives it the possibility to convene meetings and ensure North Korea remains a priority issue for the United Nations' most powerful body for the rest of February.
One Western diplomat said he hoped the council would approve an initial statement condemning the nuclear test on Tuesday and begin work on a more comprehensive council reaction.
Diplomats had said previously that the United States, South Korea and European members would want the Security Council to adopt a resolution imposing new sanctions on Pyongyang in the event of a third nuclear test in defiance of earlier council resolutions.
North Korea's previous nuclear tests prompted the Security Council to impose sanctions - including a ban on the import of nuclear and missile technology and an arms embargo - on the impoverished authoritarian state.
Getting approval on a council resolution could take weeks. While China had made clear its opposition to a new North Korean nuclear test, council diplomats say Pyongyang's ally Beijing could be expected to put up some resistance to tough new sanctions to avoid angering North Korea. But eventually, the diplomats said, China would likely approve some form of sanctions against North Korea in the coming weeks.
Japan will consider its own sanctions against North Korea which has appeared to have conducted a nuclear test, Japanese Prime Minister Shinzo Abe said Tuesday.
"I have ordered that we consider every possible way to address this issue, including our own sanctions, while cooperating with other countries," Abe told reporters after a meeting of Japan's security council.