North Korea is forging ahead with work to enrich uranium for nuclear weapons, which could add to its atomic arsenal and raise the risk it will sell nuclear know-how abroad, a study said Friday.

The report published by the Institute for Science and International Security (ISIS) came after warnings from South Korea that "North Korea's nuclear threat has progressed at a rapid pace and reached a very alarming level."

South Korea also said this week that the North is restoring facilities at its Yongbyon nuclear reactor, the source of weapons-grade plutonium in the past.

In the report titled "Taking Stock: North Korea's Uranium Enrichment Program," authors David Albright and Paul Brannan wrote that North Korea is developing centrifuges to enrich uranium.

The program is an "avenue for North Korea to increase the number and sophistication of its nuclear weapons and for it to proliferate to others who seek to build their own centrifuge programs," the authors wrote.

The ISIS report, based on procurement data obtained by governments and information from Pakistan, said the uranium program's status and location of the plants was unclear.

There was enough information to support "that North Korea has moved beyond laboratory-scale work and has the capability to build, at the very least, a pilot-scale gas centrifuge plant," the authors added.

But the report said the procurements do not suggest that Pyongyang is able to build a plant with 3,000 centrifuges, which are needed to produce enough enriched uranium for about two nuclear bombs a year.

"The most effective way to end the threats posed by North Korea's centrifuge program is through negotiations, even though that route looks currently difficult," the report said.

Six-party talks involving North and South Korea, China, Japan, Russia and the United States had previously secured North Korean pledges to give up its nuclear programs, but Pyongyang stormed out in April last year.

In the meantime, the report said, Washington and its partners must tighten existing UN sanctions to slow down North Korea's centrifuge program and make sure Pyongyang does not sell centrifuge, reactor or other nuclear technology.

While saying China has acted in support of UN sanctions against North Korea, the authors said Beijing "is not applying enough resources to detect and stop North Korea's nuclear trade."

It said North Korea obtains nuclear technology for its uranium enrichment program by either buying directly from China or using it as a transhipment point.

Mark Toner, a State Department spokesman, said he was aware of the report, but could not answer in great detail.

The study "really doesn't change our basic position which is that we call on North Korea to denuclarize and live up to its international commitments," Toner told reporters.

earlier related report
US-NKorea nuclear talks could resume in January: press
Washington (AFP) Oct 8, 2010 - The United States may resume talks with North Korea by January and six-party nuclear disarmament negotiations could also resume within months, the Wall Street Journal reported Friday.

"I would think that it's likely that over the next few months we will be reconvening with North Korea, both bilaterally, and then through the six-party process," a senior US official working on North Korea was quoted as saying.

The daily, which cited US and Asian officials, said the US-North Korean talks could take place "by January."

Six-party talks involving North and South Korea, China, Japan, Russia and the United States had previously secured North Korean pledges to give up its nuclear programs, but Pyongyang stormed out in April last year.

The Wall Street Journal said US optimism for renewed talks is based on an easing of tensions between the two Koreas as well as on "assurances" given by China, one of North Korea's few allies, that Pyongyang wants dialogue.

"The apparent success of Kim Jong Il's succession plan, US and Asian officials believe, has strengthened his position to make strategic decisions at the negotiating table and elsewhere," the newspaper added.

Kim's youngest son, Kim Jong-Un, believed aged about 27, was last week appointed a four-star general and given powerful party posts, apparently confirming his status as leader-in-waiting to his ageing and ailing father.

The Associated Press reported Friday that a senior North Korean official has given the first public confirmation that Kim's youngest son will succeed his father.

The Wall Street Journal quoted US officials as saying meanwhile that they want to renew talks with the North out of growing concerns that North Korea may be forging ahead with its nuclear weapons programs.

Pyongyang has tested two nuclear devices in the last four years.