As the UN imposed sanctions on North Korea, Clifford Coonan, in Busan, reports on the reaction in South Korea.
Scientists are still trying to work out the technical details of North Korea's nuclear weapons test at an underground site at the town of Kilju, 100 kilometres from the Chinese border, last Monday morning.
It was small for a nuclear explosion, if that is what it was, but the test has sent huge shockwaves rippling through Asia and the rest of the world, which now has to come to terms with the reality of a new, ninth member of the exclusive club of nations with nuclear capabilities.
It's a nightmare scenario - nuclear weapons in the hands of North Korea's "Dear Leader" Kim Jong-il, a maverick widely regarded as a highly dangerous, paranoid, megalomaniac, who uses terrorism and threats to get his way. The world is significantly less safe one week on.
In the South Korean capital, Seoul, there are growing calls for Washington to redeploy the tactical nuclear weapons that it pulled out in 1991, while others want South Korea to develop its own nuclear weapons. Similar demands are gaining currency in Japan, and in Taiwan, raising the prospect of an Asian arms race. The focus of the international community had long been on Iran's nuclear programme, to the undoubted chagrin of Mr Kim, who successfully steered the world's attention back to his small communist enclave by fulfilling his threat to test a nuclear device. It was a desperate bid to earn respect.
The initial reaction from around the world was nearly unanimous condemnation, with even China, North Korea's only friend in the world, slamming the test as a "brazen" act, a harsh term to use between allies.
Beijing was furious. Even though China's energy and food aid is a lifeline for Mr Kim's regime, the Chinese received only a brief warning that the test was going to take place, and this after warning Pyongyang for months not to test nuclear weapons. There was talk of abandoning a treaty Beijing signed in a spirit of communist fellow feeling in 1961, which commits China to defending North Korea if it comes under attack.
Since then, China has calmed down and moderated its reaction, calling for a resumption of the stalled six-nation talks aimed at solving the nuclear stand-off and trying to avoid the possibility of any efforts to unseat Mr Kim. China fears regime change in North Korea as it would have to bear the brunt of refugees streaming across the border and also doesn't like the prospect of a US-backed capitalist democracy like South Korea's in its back garden.
China cannot tolerate Western censure at a time when its economy is growing on the back of exports to the US and Europe, among others, and Beijing is also keen to showcase its diplomatic skills and ability to play honest broker in the region.
Underlining this role, senior Chinese diplomat Tang Jiaxuan met President George Bush to discuss ways to ease the situation, although Mr Bush's aides later acknowledged differences over how to deal with the North Korean crisis.
After apparently convincing the Americans, British and French to soften the sanctions somewhat, China backed the UN Security Council in adopting a new US draft resolution slapping non-military global sanctions on North Korea.
Nerves across the continent were badly rattled, although it is doubtful that North Korea is trying to force an escalation into open military conflict. Pyongyang more likely felt cornered and had to react somehow.
So it reacted the only way it knows how - with a focused action aimed at generating fear.
In South Korea, where they know a thing or two about living with fear, the people have developed a tough skin when it comes to the North's nuclear programme.
The South Korean defence ministry estimates that North Korea has over 13,000 rockets and missiles pointed at the capital Seoul, which is just 50 kilometres from the border and is home to around half of South Korea's 48.5 million people. Jane's International Defence Review estimates that if North Korea launched an all-out barrage, it could achieve an initial fire rate of 300,000 to 500,000 shells per hour into the Seoul area. Even without nuclear weapons, North Korea could do serious damage to its rich southern cousins.
President Roh Moo-hyun has been criticised for his soft-pedalling, "sunshine policy" on North Korea and supplying the North with too much economic aid, which may have been used in the nuclear programme. South Koreans are more concerned at the prospect of reunification with the North, which they view as an economic disaster waiting to happen.
Polls show that only 12 per cent of South Koreans see unification was an absolute necessity, down 7 percentage points from a year earlier.
Against this background, South Korea also backed the US proposal on sanctions. At a summit in Beijing, Mr Roh and his Chinese counterpart Hu Jintao agreed to support the Security Council in taking "necessary and appropriate sanctions" on the North.
The revised draft, which includes an arms and technology embargo, is believed to require a new UN resolution if any further action needs to be taken, which means that any military intervention would have to happen following fresh consultation within the council.
There are questions over whether the sanctions will make much difference - the country has lived under US embargo since the end of the Korean War in 1953. But if the North is unable to sell its goods abroad, the sanctions could work, said the Korean Institute for International Economic Policy in Seoul.
"External trade is very important for the North. If its trade with other countries is curbed, its economy will face a sharp decline, greater than the situation in the mid-1990s," it said, referring to the economic mismanagement and series of natural disasters a decade ago, causing a famine in which over two million North Koreans died.
Situated within striking range of North Korea, Japan is extremely worried at the idea of a nuclear North. Lately North Korea's third-biggest trading partner, Tokyo has also introduced its own restrictions, including a ban on imports from the North and closing Japanese ports to North Korean ships, beefing up earlier sanctions levied on the North after it conducted multiple missile tests in July.
The test highlighted the bankruptcy of nearly 20 years of diplomatic efforts to stop North Korea's nuclear ambitions and secure a nuclear-free Korean peninsula, a failure particularly keenly felt in Washington where Mr Bush has come in for criticism for the way his administration has handled the nuclear crisis.
For many years Mr Bush focused on the perceived nuclear threat posed by Iraq, which subsequently proved a groundless fear. In his 2002 State of the Union address, Mr Bush described North Korea as a member of the "axis of evil" alongside Iran and Saddam Hussein's Iraq, and said separately that he loathed Mr Kim for starving his people.
Paik Hak-soon, a North Korea analyst at the Sejong Institute outside Seoul, said labelling North Korea like that was like "trying to talk to a woman after calling her a prostitute". Mr Bush said in 2003 that his government would "not tolerate nuclear weapons in North Korea" but his strong words were not matched with firm actions on resolving the crisis.
However, analysts in Seoul say the one thing people in the region fear more than a nuclear North Korea is US military action.
Mr Bush seems set on following the UN route for the time being, having called for the swift passage of sanctions and apparently ruling out a military strike. "I believe the commander-in-chief must try all diplomatic measures before we commit our military," he said earlier this week.
Mr Kim is unlikely to take much solace from this message. He firmly believes that only nuclear weapons will stop Washington from deposing him by force, something he believes all the more fervently since the US-led invasion of fellow rogue state Iraq and toppling of Saddam Hussein.
"They want to get accepted. They honestly think in their own way that if they didn't act tough, they wouldn't just not get attention, but get invaded eventually," Michael Breen, a biographer of Kim Jong-il and longtime Korea-watcher, told the Korea Herald.
"I don't think he is prepared to give up his nuclear weapons. That would require him to trust the United States and South Korea. We may have to live with a nuclear North Korea for a while," he said.