SEOUL, South Korea -- North Korea's neighbors scrambled Wednesday to forge a common front against Pyongyang's threatened nuclear test, with South Korea warning of a regional atomic arms race that could upend the regional balance of power.
The cooperative efforts displayed by Japan, China and South Korea marked a sharp contrast with the fractured reaction to a series of North Korean missile tests in July. In that incident, China and South Korea accused Japan of overreacting.
On Wednesday, China -- the North's main ally and key benefactor -- appealed to Pyongyang to show calm and restraint, issuing an unusually pointed statement that referred to North Korea by name, instead of its usual appeals for all sides to remain calm.
Japan, China and South Korea announced a series of summit meetings over the next week to repair damaged ties and coordinate a strategy. Japanese Prime Minister Shinzo Abe will meet with Chinese President Hu Jintao on Sunday and South Korean President Roh Moo-hyun on Monday. Roh will then visit Beijing for talks with Hu and other officials Oct. 13.
The three countries are key players -- along with the United States and Russia -- in the long-stalled six-nation talks aimed at persuading the impoverished communist regime to give up its nuclear ambitions in return for badly needed economic aid.
Japan also took its case to the United Nations, pressing a divided Security Council to adopt a statement urging the North to cancel the test and return immediately to talks. Japan's draft text warned that a test would "jeopardize peace, stability and security in the region and beyond." U.S. ambassador John Bolton told reporters that members were divided on how to respond to the North.
The joint effort came a day after North Korea triggered global alarm by saying it will undertake an unprecedented nuclear test in a step toward building the atomic arsenal it views as a deterrent against any U.S. attack.
It was the first time the North has publicly announced plans to conduct a nuclear test, though recent reports have said it may be preparing one. North Korea claims to have nuclear weapons, but detonating one would be the first proof of its atomic capabilities.
Russia's defense minister voiced concern about the environmental consequences in neighboring Russian territory. "The nuclear tests in North Korea, if they take place, could cause ecological damage in Russia," Sergei Ivanov said.
on a visit to a Russian air base in Kyrgyzstan.
The United States said it has warned the communist nation not to stage a nuclear test.
"We are not going to live with a nuclear North Korea," Assistant Secretary of State Christopher Hill said Wednesday.
Hill, the chief envoy to disarmament talks, said the United States has passed a message of "deep concern" through diplomatic channels at the United Nations but has yet to hear back from North Korea.
A U.S. intelligence official, speaking on condition of anonymity, said the United States is now seeing the movement of people, materials, automobiles and other activity around one possible test site, but it could be similar to the activity that was seen a couple months ago. At that time, no test occurred.
The official noted that international observers don't have a baseline for comparison, because North Korea has never performed a nuclear test.
South Korea's top official on dealings with the North, Unification Minister Lee Jong-seok, said Wednesday there were no signs of an imminent test. And Japan's Asahi newspaper reported that two Japanese spy satellites focusing on a suspected underground test site had not observed any activities apparently connected to test preparations as of Tuesday.
While North Korean leader Kim Jong Il may decide to hold the test, it cannot be ruled out that the announcement is saber-rattling, an effort to force a change in the stalled diplomatic negotiations or some other motivating factor.
Lee, however, warned there was "a high possibility" North Korea would go ahead with a test if "efforts to resume the six-party talks fail."
North Korea has boycotted six-nation nuclear talks for nearly a year, angered by American financial restrictions imposed over the North's alleged illegal activities such as money laundering and counterfeiting.
Any display of Pyongyang's nuclear force could prompt Japan to go nuclear and trigger a regional arms race, South Korean Vice Foreign Minister Yu Myung-hwan warned. Speaking to lawmakers, Yu said such a North Korean nuclear test "could provide a pretext for Japan's nuclear armament."
"This will prompt countermoves by China or Russia and lead to a change in the balance of power in Northeast Asia," Yu said.
In a worst-case scenario, analysts have speculated, a test could push Japan to seek its own nuclear deterrent, intensifying historical tensions with China and South Korea, both of which suffered under Japanese colonial rule in the early 20th century.
Just last month, a think tank run by former Japanese Prime Minister Yasuhiro Nakasone proposed in a policy paper that Tokyo "consider the nuclear option."
The South Korean president called Wednesday for a "cool-headed and stern" response to the North's announcement, while Foreign Ministry spokesman Choo Kyu-ho said a test could cause Seoul to change its engagement policy toward the communist regime.
But a test could strain the alliance between South Korea and the United States, which has adopted a harder-line toward Pyongyang.
South Korea has consistently pursued dialogue with North Korea since their leaders first met in a historic summit in 2000. Seoul is also a main aid provider. On Wednesday it was shipping previously promised flood relief aid, including 6,400 tons of cement, despite the nuclear test threat.
"As North Korea has yet to conduct a nuclear test, it is difficult to immediately halt sending flood relief aid, which is being provided on a humanitarian basis," a ministry official said on condition of anonymity, citing official policy.
Other issues could also splinter a common front against North Korea.
Japan, the top U.S. ally in East Asia, has been the most hard-line against Pyongyang, especially since North Korea fired a test missile over its territory in 1998.
China, meanwhile, sees Pyongyang as a counterbalance to U.S. influence in its own backyard.
"North Korea's next step may be to do nothing at all, other than to sit back and watch the rest of the world argue about what to do next," Ralph Cossa, president of the Honolulu-based Pacific Forum, wrote in a report on the latest threat.
Some experts believe the North has enough fissile material to build at least a half-dozen nuclear bombs, though there are doubts about whether it could deliver them accurately on a warhead.