SEOUL, South Korea, (AP) -North Korea faced a barrage of condemnation and calls for retaliation Monday after it announced that it had set off a small atomic weapon underground, a test that thrust the secretive communist state into the elite club of nuclear-armed nations.
The United States, Japan, China and Britain led a chorus of criticism and urged action by the United Nations Security Council in response to the reported test, which fell one day after the anniversary of reclusive North Korean leader Kim Jong-il’s accession to power nine years ago.
The Security Council had warned North Korea just two days earlier not to go through with any test, and the Pyongyang government’s defiance was likely to lead to calls for stronger sanctions against the impoverished and already isolated country.
White House spokesman Tony Snow called for “immediate actions to respond to this unprovoked act” and said that the United States was closely monitoring the situation and “reaffirms its commitment to protect and defend our allies in the region.”
South Korea’s geological institute estimated that the test’s power was equivalent to 550 tons of TNT, far smaller than the two nuclear bombs the U.S. dropped on Japan in World War II.
The U.S. Geological Survey said it recorded a magnitude-4.2 seismic event in northeastern North Korea. Asian neighbors also said they registered a seismic event, but only Russia said its monitoring services had detected a nuclear explosion.
“It is 100 percent (certain) that it was an underground nuclear explosion,” said Lt. Gen. Vladimir Verkhovtsev, head of a Defense Ministry department, according to Russia’s ITAR-Tass news agency.
Although North Korea has long claimed it had the capability to produce a bomb, the test was the first manifest proof of its membership in a small club of nuclear-armed nations. A nuclear armed North Korea would dramatically alter the strategic balance of power in the Pacific region and would tend to undermine already fraying global anti-proliferation efforts.
“If the test (is) true, it will severely endanger not only Northeast Asia but also the world stability,” Japanese Foreign Minister Taro Aso warned.
Japanese Prime Minister Shinzo Abe, facing his first major foreign policy test since his recent election, called for a “calm yet stern response.”
South Korea said it had put its military on high alert, but said it noticed no unusual activity among North Korea’s troops.
China, the North’s closest ally and the impoverished nation’s main source of food, expressed its “resolute opposition” to the reported test and urged the North to return to six-party nuclear disarmament talks. It said the North “defied the universal opposition of international society and flagrantly conducted the nuclear test.”
Britain’s Prime Minister Tony Blair said the test was a “completely irresponsible act,” and its Foreign Ministry warned of international repercussions.
The White House said a test defied world opinion.
“A North Korean nuclear test would constitute a provocative act in defiance of the will of the international community and of our call to refrain from actions that would aggravate tensions in Northeast Asia,” Snow said.
Russia, which borders North Korea, had urged Pyongyang not to conduct a nuclear test. Defense Minister Sergei Ivanov last week voiced concern about the environmental consequences for Russia. The Foreign Ministry warned that a test would add to regional tensions and undermine the international nuclear nonproliferation regime.
The North has refused for a year to attend six-party international talks aimed at persuading it to disarm. The country pulled out of the Nuclear Nonproliferation Treaty in 2003 after U.S. officials accused it of a secret nuclear program, allegedly violating an earlier nuclear pact between Washington and Pyongyang.
The North’s official Korean Central News Agency said the underground test was performed successfully and there was no dangerous radioactive leakage as a result.
North Korean scientists “successfully conducted an underground nuclear test under secure conditions,” the government-controlled agency said, adding this was “a stirring time when all the people of the country are making a great leap forward in the building of a great prosperous powerful socialist nation.”
“It marks a historic event as it greatly encouraged and pleased the … people that have wished to have powerful self-reliant defense capability,” KCNA said. “It will contribute to defending the peace and stability on the Korean Peninsula and in the area around it.”
South Korea said the test was conducted at 10:36 a.m. (9:36 p.m. EDT Sunday) in Hwaderi near Kilju city on the northeast coast. South Korean intelligence officials said the seismic wave had been detected in North Hamkyung province, the agency said.
No increase in radiation levels was detected in Russia’s Primorye territory, which borders North Korea, the Russian news agency Interfax quoted regional meteorological service spokesman Sergei Slobodchikov as saying. Vladivostok, a large port city on Russia’s Pacific Coast, is about 60 miles from the short border with North Korea.
South Korean President Roh Moo-hyun convened a meeting of security advisers over the test, Yonhap reported. The Japanese government set up a task force in response, Kyodo news agency said.
A U.N. Security Council resolution adopted in July after a series of North Korean missile launches imposed limited sanctions on North Korea and demanded that the reclusive communist nation suspend its ballistic missile program — a demand the North immediately rejected.
The resolution bans all U.N. member states from selling material or technology for missiles or weapons of mass destruction to North Korea — and it bans all countries from receiving missiles, banned weapons or technology from Pyongyang.
Speculation over a possible North Korean test arose earlier this year after U.S. and Japanese reports cited suspicious activity at a suspected underground test site.
South Korean stocks plunged Monday following North Korea’s announcement of the test. The South Korean won also fell sharply. The benchmark Korea Composite Stock Price Index, or Kospi, fell as low as 1,303.62, or 3.6 percent.
Markets in South Korea, the world’s 10th largest economy, have long been considered vulnerable to potential geopolitical risks emanating from the North. The two countries, which fought the 1950-53 Korean War, are divided by the world’s most heavily armed border.
The two Koreas, which fought a 1950-53 war that ended in a cease-fire that has yet to be replaced with peace treaty, are divided by the world’s most heavily armed border. However, they have made unprecedented strides toward reconciliation since their leaders met at their first-and-only summit in 2000.
The South had planned to ship 4,000 tons of cement to the North on Tuesday as emergency relief following massive flooding there, but decided to delay it, Yonhap reported, quoting an unidentified Unification Ministry official.
South Korea had said the one-time aid shipment was separate from its regular humanitarian aid to the North, which it has halted after Pyongyang’s missile launches in July.
Impoverished and isolated North Korea has relied on foreign aid to feed its 23 million people since its state-run farming system collapsed in the 1990s following decades of mismanagement and the loss of Soviet subsidies.