The shock of an underground nuclear blast in North Korea's mountainous northeast late Sunday sent tremors of concern through Northeast Asia, uniting often disputatious powers against the prospect of a nuclear power rising within easy missile range.
The news of the test also dealt a blow to nearly a decade of efforts at reconciliation between North and South Korea – and presented a loss of face for China, seen as having pivotal influence in Pyongyang.
The North's display of nuclear prowess "will bring about some new perspectives on regional security," said Park Young Ho, senior fellow at the Korea Institute of National Unification. "Japan and even South Korea may have some temptation to develop nuclear weapons."
Japan's new prime minister, Shinzo Abe, on a whirlwind get-acquainted tour of China and then Seoul, wrapped up with a plea for the world community to "address the situation with harsher measures."
Mr. Abe conveyed the sense that the test, announced by Pyongyang shortly after he arrived in Seoul, had helped significantly in resolving deep differences between Japan and South Korea as well as China. "We saw eye to eye," he said flatly after standing beside South Korean President Roh Moo-Hyun.
In Washington, President Bush said Monday that he had talked with China, South Korea, Russia, and Japan – members of the stalled six-party nuclear talks on North Korea – all of whom had reiterated their commitment to a nuclear-free Korean peninsula.
The UN Security Council Monday unanimously condemned the North's test and was to begin discussions on a US-drafted resolution. John Bolton, the US Ambassador to the UN, said Washington wants to go beyond the resolution the Security Council adopted in July, making it tougher for North Korea to produce or export weapons of mass destruction. Members urged the North to refrain from further testing and to return to talks.
China issued a stern rebuke to North Korea in the wake of failed Chinese efforts to bring North Korea back to six-party talks or to head off missile tests by the North in early July. It also expressed anger at the fact that the nuclear test occurred the day after Abe's visit to Beijing.
Beijing's strong response may signal a willingness to accede to calls in the UN Security Council for tougher action on North Korea's nuclear program, including economic sanctions that China and South Korea had earlier opposed.
China's Foreign Ministry charged that North Korea had "ignored universal opposition of the international community and flagrantly conducted the nuclear test" – a reaction that contrasted with its relatively mild response to North Korea's conventional missile tests in July.
China and South Korea had both earlier criticized Japan for exaggerating the North Korean nuclear threat, accusing Japanese rightists of building up North Korea as a dangerous enemy in order to provide the rationale for doing away with Article Nine of Japan's postwar constitution, which forbids Japan from sending troops overseas.
At that time, China raised concern about Japan emerging as an expansionist power, jeopardizing regional security. North Korea's nuclear test rekindled fears of a regional nuclear-arms race, but there was no trace in statements from Beijing or Seoul after the announcement of the test of the kind of anti-Japanese sentiment that has reverberated in recent years.
The contentious question of whether Abe would follow the lead in visiting Japan's Yasukuni shrine honoring Japan's war dead, including convicted war criminals, was barely mentioned.
Mr. Roh, who inherited the "Sunshine Policy" of economic engagement with the North, said his government would find it "increasingly difficult to stick to its engagement policy." While South Korea would not give up its desire for peaceful dialogue, he said, "we may not continue to be patient and to yield to North Korea's demands."
Roh's remarks reflected rising conservative pressure to relinquish what are seen as leftist policies – and to consider closing down business and tourist programs. While warning of possible "stern measures," however, Roh did not specify exactly what he might do.
South Korea may consider suspension of operations by South Korean companies in a special economic zone at Kaesong, across the border with North Korea and about 40 miles north of Seoul, and of tours by South Koreans to the Mount Kumkang resort region in which South Korea's Hyundai group has invested about $ billion.
The North Korean test also seemed likely to bring South Korea closer to the United States after increasingly strained relations over what the South has seen as the "hard line" of the White House regarding what Bush famously dubbed the "axis of evil," running from Iraq and Iran to North Korea.
"Korea and the US will get closer to convergence in putting pressure on North Korea,"said Kim Sung Han, professor at the Institute of Foreign Affairs and National Security, an adjunct of the foreign ministry.
South Korea, he said, "might join the Proliferation Security Initiative" – a US-sponsored effort to get nations to band together to stop the proliferation of weapons of mass destruction. South Korea has so far refused to join PSI, preferring observer status at interdiction exercises in which participating nations practice stopping and boarding vessels.
Another option, said Mr. Kim, would be for the government to "consider joint missile defense" with the US and possibly even Japan – a level of interdependence that the Roh government had previously opposed.
China's shift was already apparent last week when North Korea announced its nuclear intentions. Beijing ratcheted up its rhetoric, warning of "grave consequences" that would follow any test, departing from its usual calls for dialogue and backing a nonbinding UN Security Council resolution urging North Korea to desist.
Abe told reporters Sunday, after meeting China's top leaders, that Japan and China agreed that a nuclear test would be "intolerable." When he heard about the test on Monday, he called it "unpardonable."
While professing accord with South Korea's Roh, Abe delivered what was seen as a rebuke for the soft measures adopted till now by the UN Security Council. "The international community must address the situation with harsh measures," he said, hinting at the tough response Japan advocates.
China has lobbied for dialogue and consultation with North Korea, and has chaired the on-off six-party talks, last held in November in Beijing.
But China may now be confronting a failed policy, experts say. "Promoting dialogue with North Korea as the only way was a mistake. That mistake has given North Korea time to develop a nuclear weapon," says Zhang Liangui, a professor at China's Central Party School.
"China doesn't have any cards to play any more," he adds. "Its policy towards North Korea is a failure."
Chinese state media, in contrast to the South Korea's media, downplayed test news.
North Korea depends on China for oil, food, and other essential supplies. "As close as lips and teeth," was the old Communist description of bilateral relations, though North Korea has always been the dependent junior partner. Since then, post-cold-war changes have left the North reluctant to embrace economic reforms that have brought prosperity to China.
Analysts say China is likely to edge closer to other members of the UN Security Council as it grapples with the test. In the past, China has clashed with the US over sanctions on North Korea, which China fears could destabilize its neighbor. Hundreds of thousands of North Koreans have crossed the border with China in recent years, fleeing poverty and repression. But this provocation, and Beijing's failure to rein in its ally, may force a change of stance.
"This test will push the US, Japan, and China closer. China will have a difficult time blocking any Security Council resolution," said Yu Tiejun, a professor at Peking University.
"If the US, Japan, and other members of the Security Council are going to take tough measures on North Korea, probably in the early stages China will say something different and urge restraint, but finally China will agree to resolute action," says Jin Linbo, a researcher at the China Institute for International Studies, a government-funded think tank.
North Korea's claim that it conducted a nuclear test Sunday night raised political risks a notch higher for businesses in the region, and markets slid southward accordingly.
A UN Security Council resolution adopted in July imposed limited sanctions on North Korea and demanded that it suspend its ballistic missile program. US officials said Monday that one proposal now was to put pressure on countries to crack down on banks and businesses aiding the North's weapons programs and ensure close scrutiny of its cargo ships, said officials in Washington.
The US Treasury Department last year began a broad initiative to sever North Korean links to foreign banks because of its alleged counterfeiting and other financial crimes. Those banks hold accounts belonging to key members of North Korea's elite, which would include military commanders.
A July 9 story from The Sunday Times of London reported that "since the collapse of six-nation talks in Beijing on North Korea's nuclear weapons, the US and its allies have also tightened the screws on [Kim Jong Il's] clandestine fundraising, which generated some $500 million a year for the regime."
Also, the Times reported, a "covert" program to subvert missile traffic moving in and out of the country involves the interception of North Korean ships and high-level air and naval surveillance operations.
Sunday's nuclear test deepens concerns that Pyongyang could export its technology to Tehran. North Korea is widely known to have helped Iran develop its Shahab missile program, and European and other Western intelligence sources say North Korean technicians and nuclear experts have helped to train Iranian scientists.