WASHINGTON — North Korea said today that it had set off its first nuclear test, becoming the eighth country in history, and arguably the most unstable and most dangerous, to join the club of nuclear-weapons states.
The test came just two days after the country was warned by the U.N. Security Council that the action could lead to severe consequences.
American officials cautioned that they had not yet received any confirmation that the test had occurred. But senior Bush administration officials said they had little reason to doubt the country’s announcement.
The U.S. Geological Survey said it had detected a 4.2-magnitude seismic event in northeastern North Korea.
In South Korea, the country that fought a bloody war with the North for three years and has lived with an uneasy truce and failed efforts at reconciliation for more than half a century, officials announced they think an explosion occurred about 11:36 a.m. today — with a magnitude of 3.58.
They identified the source of the explosion as North Hamgyong Province, the area where American spy satellites have been focused for several years on a variety of suspected underground test sites.
That was less than an hour after North Korean officials had called their counterparts in China and warned them that a test was just minutes away.
The Chinese, who have been North Korea’s main ally, sent an emergency alert to Washington through the U.S. Embassy in Beijing, and President Bush was told shortly after 10 p.m. Sunday by his national-security adviser, Stephen Hadley, that a test was imminent.
The North’s decision to set off a nuclear device could profoundly change the politics of Asia.
The test occurred less than two weeks after Japan elected a new, more nationalistic prime minister, Shinzo Abe, and just as the country was renewing a debate about whether its ban on possessing nuclear weapons — deeply felt in a country that saw two of its cities incinerated in 1945 — still makes strategic sense.
The peninsula shook just as Abe arrived in South Korea for the first time as prime minister, in an effort to repair a badly strained relationship, having just visited with Chinese leaders in Beijing.
Now, Tokyo and Washington are expected to put even more pressure on the South Korean government to terminate its “sunshine policy” of trade, tourism and openings to the North — a policy that has been the source of enormous tension between Seoul and Washington since Bush took office.
The explosion was the product of nearly four decades of work by North Korea, one of the world’s poorest and most isolated countries, a country of 23 million people that appears constantly fearful that its far richer, more powerful neighbors — and particularly the United States — will try to unseat its regime.
“I think they just had their military plan to demonstrate that no one could mess with them, and they weren’t going to be deterred, not even by the Chinese,” a senior American official who deals with the country said late Sunday evening. “In the end, there was just no stopping them.”
But the explosion was also the product of more than two decades of diplomatic failure, spread over at least three presidencies. American spy satellites saw the North building a good-sized nuclear reactor in the early 1980s, and by the early 1990s the CIA estimated that the country could have one or two nuclear weapons. But a series of diplomatic efforts to “freeze” the nuclear program — including a 1994 accord signed with the Clinton administration — ultimately broke down, amid distrust and recriminations on both sides.
Three years ago, just as Bush was sending American troops toward Iraq, the North threw out the few remaining international weapons inspectors living at their nuclear complex in Yongbyon and moved 8,000 nuclear-fuel rods they had kept under lock and key. Those rods contained enough plutonium, experts said, to produce five or six nuclear weapons, though it is unclear how many — apart from the one presumably tested — the North now stockpiles.
North Korea’s decision to conduct the test demonstrated what the world has suspected for years: The country has joined India, Pakistan and Israel as one of the world’s “undeclared” nuclear powers.
India and Pakistan conducted tests in 1998; Israel has never acknowledged conducting a test or possessing a weapon. But by actually setting off a weapon, if that is proved, North Korea has chosen to end years of carefully crafted and diplomatically useful ambiguity about its capabilities.
But the big fear about North Korea, American officials have long said, has less to do with its ability to lash out than it does with its proclivity to proliferate. The country has never produced a weapon that it did not ultimately sell. It has provided missiles to Iran, Syria and Pakistan, among other nations.
It is for that reason Bush declared in 2003 that the United States would never “tolerate” a nuclear-armed North Korea. But he has never defined what he means by “tolerate.” Sunday night Tony Snow, Bush’s press secretary, said the United States would now go to the United Nations to determine “what our next steps should be in response to this very serious step.”
