North Korea claims final stage uranium enrichment

North Korea said Friday that it is in the final stages of enriching uranium, a process that could give the nation a second way to make nuclear bombs in addition to its known plutonium-based program.

North Korea informed the UN Security Council it is forging ahead with its nuclear programs in spite of international calls to abandon its atomic ambitions, the official Korean Central News Agency said in a report early today.

The dispatch said plutonium "is being weaponized," and that uranium enrichment — a program North Korea revealed in recent months — was entering the "completion phase."

The US and North Korea's neighbors had been negotiating for years with North Korea to dismantle its plutonium-based nuclear program, which experts say has yielded enough weaponized plutonium for at least half a dozen atomic bombs.

Experts had long suspected that the North also had a covert uranium enrichment program, which would give the regime a second source of nuclear material. North Korea for years denied the claim but in response to UN sanctions announced in June that it would begin uranium enrichment.

It's easier to build nuclear bombs using enriched uranium than reprocessing plutonium, and uranium can be enriched in relatively inconspicuous factories better able to evade spy-satellite detection, according to experts in the U.S. and at South Korea's Institute of Nuclear Nonproliferation and Control.

Uranium-based bombs may also work without requiring test explosions like the two carried out by North Korea in May and in 2006 for plutonium-based weapons.

However, plutonium bombs have more potential to be miniaturized to fit on top of a missile, one expert, Ivan Oelrich of the Federation of American Scientists, has said.

North Korea is not believed to have mastered making a nuclear bomb small enough to mount in a long-range missile. An April rocket launch widely condemned by international powers and the UN Security Council was seen by many as a test of its long-range missile technology.

Friday's statement comes amid a series of conciliatory moves after months of provocation, from the April rocket launch and May nuclear test to the test-firing of a flurry of missiles.

North Korea called its actions a response to the Security Council's decision to tighten sanctions against the regime as punishment for the May nuclear test, a resolution KCNA called a "wanton violation" of the country's sovereignty.

The US, China, Japan, Russia and South Korea have been trying for years to persuade North Korea to dismantle its nuclear program in exchange for much-needed aid and other concessions. Pyongyang walked away from the talks earlier this year.

The North says it needs the nuclear program as a security guarantee against a threat from the U.S., which has 28,500 troops based in South Korea, which technically remains at war with the North because their three-year conflict in the early 1950s ended in a truce, not a peace treaty.

"We are prepared for both dialogue and sanctions," the KCNA report said, warning it would be left with no choice but to take "yet stronger self-defensive countermeasures" if the standoff continues. It did not elaborate on the possible countermeasures.

South Korea's Foreign Ministry expressed regret and urged the communist country to abandon its nuclear weapons programs and return to the stalled disarmament talks.

"The North's move to continue provocative steps ... can never be tolerated. We will deal with North Korea's threats and provocative acts in a stern and consistent manner," the ministry said in a statement.

In Washington, a US State Department spokesman said Thursday night that he had no immediate comment.

The United States' envoy on North Korea, meanwhile, was in Beijing for talks with Chinese officials on how to get North Korea back to disarmament talks. Stephen Bosworth was to arrive in Seoul later Friday to speak to South Korean officials before traveling to Tokyo on Sunday.

His visit to the region aims to "continue consultations with our partners and allies on how to best convince North Korea that it must live up to its obligations ... and take irreversible steps toward complete denuclearization," the U.S. Embassy in Beijing said in a statement.

KCNA said Friday that North Korea has never objected to the denuclearization of the Korean peninsula, and left open possibility for dialogue with some permanent members of the Security Council — an apparent reference to the U.S.

The North has long sought one-on-one negotiations with Washington. The US has said it is willing to hold direct talks with Pyongyang, but under the framework of the six-nation disarmament talks.

In a promising sign, North Korea has freed two jailed American journalists and five detained South Koreans in recent weeks. The two Koreas also agreed to restart the reunions of families separated by the 1950-53 Korean War, and restored regular cross-border traffic to a joint factory park in the North.

Unification Ministry spokesman Chun Hae-sung expressed hope that the North's latest move would not disrupt the family reunions set for later this month.