BEIJING // A defiant North Korea yesterday staged its most powerful nuclear test yet and warned of stronger action to follow if the ensuing wave of global condemnation translated into tougher sanctions.
Global powers, including Pyongyang's sole major ally, China, denounced the test, which the North said was of a "miniaturised" device - a claim that will fuel concerns it has moved closer to fitting a warhead on a ballistic missile.
The underground test, which set off powerful seismic waves, drew immediate condemnation from Washington, Russia, Japan and others. Even China summoned the North's ambassador to protest. The US president, Barack Obama, called it a "highly provocative act" that demands "swift and credible action by the international community".
North Korea said its third test, after previous detonations in 2006 and 2009 that triggered a raft of UN sanctions, was a direct riposte to US "hostility". The UN Security Council was expected to debate new measures when it meets today in New York, with the United States and its allies likely to push hard for China to get tough with its erratic ally.
"Essentially, now Pyongyang's nuclear warheads can reach the United States," said a Chinese state-controlled CCTV anchorwoman in a live analysis of the event, characterising it as "an importance milestone" in North Korea's leverage against Washington. Pyongyang has been unsuccessfully negotiating a denuclearisation-for-aid deal with the US for years.
China is widely seen as the only country with any leverage over Pyongyang. However, it has long been blamed by the international community for "shielding" the North despite the latter's various belligerent acts. Bound by Cold War solidarity, the duo fought side by side against the US and its allies during the 1950-53 Korean War.
Preliminary estimates by South Korea suggested yesterday's test, at 6 to 7 seven kilotons, was much more powerful than the previous two. The yields of those tests were estimated at 1 kiloton and 2 to 6 kilotons, respectively. By comparison, US nuclear bombs that flattened Nagasaki and Hiroshima during the Second World War were estimated at 13 kilotons and 22 kilotons, respectively.
"The most important technical aspect of the test is the blast power. Estimates vary, but it is closer to the level that made me think that North Korea has succeeded in proving that it now has lighter yet more powerful nuclear weapons capability," Lim Soo-ho, a North Korea analyst with the Samsung Economic Research Institute in Seoul, said yesterday.
Analysts say a key point to watch in the coming days during the Security Council deliberation is how much China and the US will be able to narrow their differences.
"The US wants comprehensive and severe financial sanctions. China doesn't want to go that far. The US will also want the Proliferation Security Initiative (a multinational effort to stop trafficking of weapons of mass destruction) against North Korea. China opposes the idea," said Shi Yinhong, an international relations expert at Renmin University in Beijing.
How China handles North Korea this time will be a matter of credibility of China's foreign policy too, as it has been making efforts to project the image of a "responsible power" in international affairs.
Indeed, observers say this time Beijing's patience with North Korea may be wearing thin as the rift between them appears to have deepened over the nuclear testings. China spoke out much more openly against North Korea's satellite launch in December than it has against most past North Korean violations, and it supported UN sanctions.
But Stephanie Kleine-Ahlbrandt, the North-east Asia Director with the International Crisis Group, predicts that at the end of the day, the Security Council members will be "unlikely to be able to dissuade North Korea from continuing to develop its nuclear capability because China will only go so far, because it prioritises stability over denuclearisation on North Korea".
A Chinese analyst with a state-run think tank in Beijing agreed. He said China's aim at the UN Security Council is to warn North Korea, not corner North Korea. "China will join the UN to engineer certain punitive measures against Pyongyang," he said.
"That may make Pyongyang unhappy and strain the two countries' ties. But after some time passes, the ties will be back on a normal track. We need each other strategically in East Asia.".
Several UN resolutions bar North Korea from conducting nuclear or missile tests.
* With additional reporting from the Associated Press and Agence France-Presse