SEOUL, South Korea — North Korea completed a successful test of a nuclear weapon late Sunday night, a senior Bush administration official confirmed to FOX News.
The official said, however, that initial readings from South Korea reported only a 3.58-magnitude seismic reaction, which is smaller than what would be expected from the 4-kiloton explosion the communist nation sought. To put the bomb’s capabilities in context, a 20-kiloton explosion could conceivably kill 200,000 people.
The U.S. Geological Survey, however, said it detected a 4.2-magnitude tremor at 10:35 p.m. EDT, which could mean the device was potentially deadlier than initially believed. Australia also said there was seismic confirmation that North Korea conducted a nuclear test.
“It was a success from their perspective in that they achieved a nuclear yield, though that is not very difficult,” the official said. “It’s within their technical capabilities.”
U.S. officials told FOX News’ Bret Baier that they were warned by allies in advance of the test. China reportedly received a 20-minute heads up and immediately notified officials in the U.S., Japan and South Korea.
The test is North Korea’s first-ever detonation of an atomic device, but the nation as long claimed to have nuclear capabilities.
White House press secretary Tony Snow said that the White House is not officially confirming that there was a nuclear test.
Snow said the U.S. had spoken to the Chinese and had contact with the South Koreans. If they confirm that the seismic event was a nuclear test, John Bolton will call for an emergency session of the U.N. Security Council, Snow said.
Bush administration officials say they will push for an “extremely strong U.N. resolution against North Korea that would make it illegal to transfer missile and missile-related items, materials, goods and technology for North Korean weapons of mass destruction programs.”
U.S. officials say the White House will seek “much stronger punitive measures” on general trade with North Korea, although they do not believe the country’s oil supplies will be targeted.
The test sparked condemnation from regional powers who said that, if confirmed, would be a serious threat to regional stability.
The North’s official Korean Central News Agency said the underground test was performed successfully “with indigenous wisdom and technology 100 percent,” and that no radiation leaked from that test site.
“It marks a historic event as it greatly encouraged and pleased the (Korean People’s Army) and 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.”
Japan’s top government spokesman said a reported North Korean test would post a serious threat to the stability in the region and a provocation.
China, the North’s closest ally, said Beijing “resolutely opposes” the North Korean nuclear test and hopes Pyongyang will return to disarmament talks.
U.S. and South Korean officials could not immediately confirm that an actual test had occurred.
The U.N. Security Council was expected to discuss the reported North Korean test Monday, and the United States and Japan are likely to press for a resolution imposing additional sanctions on Pyongyang. The council last week issued a statement condemning plans for a test.
A resolution adopted in July after a series of North Korean missile launches imposed limited sanctions on North Korea and demanded the country rejoin international nuclear talks — a demand the North immediately rejected.
Also, South Korea’s Foreign Minister Ban Ki-moon was expected later Monday to be nominated as the next secretary-general of the United Nations by the Security Council. Ban has said he would use the post, which he would assume after Kofi Annan’s term expires at the end of the year, to press for a resolution of the North Korean nuclear standoff.
The North has refused for a year to attend international talks aimed at persuading it to abandon its nuclear ambitions. 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 is believed to have enough radioactive material for about a half-dozen bombs, using plutonium from its main nuclear reactor located at Yongbyon, north of the capital Pyongyang.
The North also has active missile programs, but it isn’t believed to have an atomic bomb design small and light enough to be mounted on a long-range rocket that could strike targets as far as the U.S.
If confirmed, the North would be the ninth country in the world known to have nuclear weapons. The other countries are the United States, Russia, France, China, Britain, India, Pakistan and Israel.
South Korean President Roh Moo-hyun was holding an emergency meeting Monday of top security officials, and Seoul was consulting with allies on intelligence about the reported test, presidential spokesman Yoon Tae-young said.
South Korea’s Defense Ministry said the alert level of the military had been raised in response to the claimed nuclear test.
The test came amid intense diplomatic efforts aimed at heading off the move.
Japan’s new prime minister, Shinzo Abe, arrived Monday in Seoul for meetings with President Roh Moo-hyun that had been intended to address strains in relations between Japan and South Korea over territorial and historical disputes, but was overshadowed by news of the nuclear test.
“We must collect and analyze information to determine whether North Korea actually conducted the test,” Abe told reporters upon his arrival.
On Sunday in Beijing, Abe and Chinese President Hu Jintao had pledged to work together to avert a North Korean test.