SEOUL, 10 October 2006 — North Korea faced a barrage of global condemnation and calls for harsh sanctions yesterday after it announced that it had set off an atomic weapon underground, a test that thrusts the secretive communist state into the elite club of nuclear-armed nations.

The explosion prompted worldwide concern it could seriously destabilize the region, and even Pyongyang’s ally China said it strongly opposed the move. South Korea’s spy chief said there were possible indications the North was moving to conduct more tests.

The United States called for immediate UN Security Council action and, along with Japan, was expected to press for more sanctions on the impoverished North.

In Washington, US President George W. Bush branded the nuclear test, in defiance of a Security Council resolution adopted only last Friday, “a threat to international peace and security” and pressed for an immediate response from the Council.

After an emergency session on the crisis, the 15-member Council “strongly condemned” Pyongyang’s action and vowed a “strong and swift” response, its president said. Japan’s UN envoy Kenzo Oshima, the Council president for October, told reporters that the Council also urged North Korea “to refrain from further testing” and return to six-nation disarmament talks.

Council members were meeting to fine-tune a draft resolution circulated by the United States to respond to Pyongyang’s defiance. Oshima said members wanted “to find appropriate measures in order to respond to this act of DPRK which poses a threat to peace and security in the region and beyond.”

Earlier his US counterpart John Bolton said that Washington sought action under Chapter 7 of the UN Charter, setting in motion a process that could lead to sanctions or even military action.

There were conflicting reports on the size of the blast. South Korea said it was relatively small, while Russia said it had been perhaps as powerful as the nuclear bombs the US dropped on Japan during World War II.

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 the 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, adding that it was “a great leap forward in the building of a great prosperous powerful socialist nation.” If details of the test are confirmed, North Korea would be the ninth country known to have nuclear weapons, along with the United States, Russia, France, China, Britain, India, Pakistan and Israel. A nuclear North Korea would dramatically alter the strategic balance of power in the Pacific region and seriously undermine global anti-proliferation efforts. Japanese Prime Minister Shinzo Abe said the test would mark the beginning of a “dangerous nuclear age” in north Asia.

Australia and South Korea said there was seismic confirmation that pointed to a nuclear test, and a top Russian military officer confirmed the device tested was a nuclear weapon, the Itar-Tass news agency reported. However, Japan and the United States said they couldn’t immediately confirm a nuclear test. South Korea’s seismic monitoring center said a magnitude 3.6 tremor felt at the time of the nuclear test was not a natural occurrence. The size of the tremor could indicate an explosive equivalent to 550 tons of TNT, said Park Chang-soo, spokesman at the Korea Institute of Geoscience and Mineral Resources — which would be far smaller than the nuclear bombs the US dropped on Japan in World War II. But in televised comments, Russia’s Defense Minister Sergei Ivanov said that the force of the blast was between five and 15 kilotons.

Intelligence officials told South Korea’s Parliament the test appeared to have been carried out in a 360-meter-high mountain tunnel northwest of the Musudan missile base in the Hwadaeri region, according to lawmaker Chung Hyong-keun.

He quoted an intelligence official as saying: “In consideration of the height of the mountain, the test appeared to have been done in a horizontal tunnel.”

Iranian state radio blamed Pyongyang’s nuclear test on US pressure, saying the test “was a reaction to America’s threats and humiliation.” Iran has said it will not abandon uranium enrichment, despite the threat of international sanctions over its disputed nuclear program, which Tehran insists is purely for peaceful purposes to be used for nuclear energy.

The Arab League called for a return to political negotiations. Arab League Secretary-General Amr Moussa called for “speedy return to political negotiations with regards the North Korean nuclear file in order to contain the situation.”

“The world does not need any more nuclear tests and does not need more tension,” Moussa said.

Pakistan’s Foreign Ministry criticized North Korea, saying its test could spark a proliferation “chain reaction.” “It is regrettable that the DPRK chose to ignore the advice of the international community not to test a nuclear weapon,” ministry spokeswoman Tasnim Aslam told a news conference in Islamabad. “Pakistan deplores the announcement by the Democratic People’s Republic of Korea that it has conducted a nuclear test,” Aslam said. “This will be a destabilizing development for the region.”

Aslam said the North Korean test was not linked to Pakistani nuclear technology that was delivered to the Pyongyang regime by disgraced Pakistani nuclear program founder Abdul Qadeer Khan.

“There is absolutely no link between the nuclear test conducted by North Korea or what might have gone on between Dr. A.Q. Khan and the North Korean government,” Aslam said. “The North Korean program is plutonium-based and Pakistan’s is mainly uranium based.”