SEOUL, South Korea - North Korea threatened Wednesday to conduct nuclear and missile tests unless the UN apologizes for criticizing its April 5 rocket launch, dramatically raising its stake in the worsening standoff over its atomic programs.
Pyongyang's Foreign Ministry said in a statement the country "will be compelled to take additional self-defensive measures" unless the UN Security Council apologizes immediately. "The measures will include nuclear tests and test-firings of intercontinental ballistic missiles."
The North's ministry also said the country would build a light-water nuclear reactor and start developing technologies to produce nuclear fuel, a threat that experts said indicated the country would start enriching uranium -- which can be used in the production of a nuclear bomb.
The current nuclear standoff flared in late 2002 after Washington raised allegations that Pyongyang had a clandestine nuclear program based on enriched uranium in addition to a separate one based on plutonium. The North has strongly denied the allegations.
North Korea is known for brinksmanship and harsh rhetoric, but it is unusual for it to threaten a nuclear test.
Pyongyang conducted its first-ever atomic test blast in 2006 and is thought to have enough plutonium to make at least half a dozen nuclear bombs. But experts have said the country is not believed to have mastered the technology to make a nuclear warhead small enough to put on a missile.
The UN Council adopted a statement this month denouncing the North's April 5 rocket launch and calling for tightening sanctions. Pyongyang has claimed the rebuke is unfair because the liftoff was a peaceful satellite launch. But the U.S. and others believe it was a test of long-range missile technology.
Wednesday's threat came days after the North said it had begun reprocessing spent nuclear fuel rods at its Yongbyon nuclear complex -- a move aimed at harvesting weapons-grade plutonium. That announcement came hours after the UN blacklisted three North Korean companies.
The Security Council should apologize for infringing on the North's sovereignty "withdraw all its unreasonable and discriminative resolutions and decisions" against the North, the ministry said in a statement carried by the official Korean Central News Agency.
Later Wednesday, South Korea's Foreign Ministry expressed "serious concerns" over the North's threat, accusing the country of "directly challenging" the international community.
"We make it clear that the international responsibility for worsening the situation will be entirely on North Korea," the ministry said in a statement.
Professor Kim Yong-hyun at Seoul's Dongguk University said the North's threat "appears to be rhetoric for now."
"The North is trying to maximize the stakes as the United States keeps ignoring it," he said. But the expert also said the communist could gradually put the threat into action depending on reaction from Washington.
Yang Moo-jin, a professor at the University of North Korean Studies, said the North appears to have already begun preparations to conduct nuclear and missile tests, given it is demanding "an unrealistic, unprecedented" demand -- a UN apology. He said the threat to build a light-water reactor "of course" meant Pyongyang would start a uranium enrichment program.
Yang, however, said the North would eventually withdraw its nuclear and missile threats, both targeting the U.S., if it achieves its main goal of wresting direct talks with Washington.
Under a 2007 six-nation deal, North Korea agreed to disable its main nuclear complex in Yongbyon north of Pyongyang in return for 1 million tons of fuel oil and other concessions. In June 2008, North Korea blew up the cooling tower there in a dramatic show of its commitment to denuclearization.
But disablement came to halt a month later as Pyongyang wrangled with Washington over how to verify its past atomic activities. The latest round of talks, in December, failed to push the process forward.
The negotiations involve China, Japan, the two Koreas, Russia and the U.S.
