North Korea Hides New Nuclear Site, Evidence Suggests
July 19, 2003......................................................President Takes a Softer Stance on North Korea
WASHINGTON,  — American and Asian officials with access to the latest intelligence on North Korea say strong evidence has emerged in recent weeks that the country has built a second, secret plant for producing weapons-grade plutonium, complicating both the diplomatic strategy for ending the program and the military options if that diplomacy fails. 

The discovery of the new evidence, which one senior administration official cautioned was "very worrisome, but still not conclusive," came just as North Korea declared to the United States 11 days ago that it had completed reprocessing 8,000 spent nuclear fuel rods, enough to make a half dozen or so nuclear weapons. 

American officials have said they cannot verify that claim, though they confirm that sensors set up on North Korea's borders have begun to detect elevated levels of krypton 85, a gas emitted as spent fuel is converted into plutonium. 

What concerns American, South Korean and Japanese analysts, however, is not simply the presence of the hard-to-detect gas but its source. While American satellites have been focused for years on North Korea's main nuclear plant, at Yongbyon, the computer analyses that track the gases as they are blown across the Korean Peninsula appeared to rule out the Yongbyon reprocessing plant as their origin. Instead, the analysis strongly suggests that the gas originated from a second, secret plant, perhaps buried in the mountains. 

American officials have long suspected that North Korea would try to build a second plant to protect itself against a pre-emptive strike by the United States. The United States even demanded an inspection of one underground site five years ago, only to find it empty, but this is the first time evidence has emerged that a second plant may be in operation. 

"This takes a very hard problem and makes it infinitely more complicated," said one Asian official who has been briefed on the American intelligence. "How can you verify that they have stopped a program like this if you don't know where everything is?" 

Indeed, there may now be at least two hidden facilities with the capacity to produce material for nuclear weapons. In October, confronted with American evidence, North Korean officials admitted that they had clandestinely built a plant intended to produce uranium, another fuel for a bomb. (It is the same approach Saddam Hussein tried in the early 1990's, and that Iran is pursuing today.) American officials say they have never found that plant, though they believe it is still a few years away from full-scale production. 

If it turns out that the current evidence is being properly interpreted, and a second plutonium plant also exists, President Bush may not even have the option that President Bill Clinton briefly considered in 1994: using a military strike or sabotage to prevent North Korea from producing significant amounts of weapons-grade material. Still, Mr. Bush has vowed that he "will not tolerate" a nuclear North Korea. 

American intelligence officials say they are wary about making any final judgments about the new evidence. They are keenly aware that C.I.A. assessments of Iraq's nuclear program have touched off a national debate over whether intelligence was exaggerated, and have made all the agency's findings suspect. 

That issue has also put the White House at odds with George J. Tenet, the director of central intelligence, who knows that the White House is going to extraordinary lengths to avoid calling the nuclear confrontation with North Korea a crisis. So far, White House officials have been told only informally of the new evidence and have not been fully briefed about its potential implications, administration officials say. 

But each week the White House's effort to sound low-key is being undercut by both North Korea's aggressive statements and new evidence that the country is now driving toward production. On Friday, the director of the International Atomic Energy Agency, Mohamed ElBaradei, who angered the White House by questioning its evidence about Iraq, expressed grave concerns about North Korea.

The situation in North Korea "is currently the most immediate and most serious threat to the nuclear nonproliferation regime," he said from his headquarters in Vienna. It is not clear if he was aware of the newest evidence when he spoke.

North Korea's stance regarding its nuclear program is strikingly different than Iraq's was. After the North Korean government threw out I.A.E.A. inspectors on New Year's Eve, its government acknowledged — even boasted of — its nuclear weapons program. The Bush administration has suspected that some of the claims amount to bluffing, an effort by North Korea to force the world to give it aid on its terms in return for re-freezing, or perhaps dismantling, its program. Mr. Bush has called the country's efforts "blackmail," and he said he would not give in. 

But behind the scenes, the North Korean declarations have hardly been dismissed. American intelligence officials have been pouring tremendous resources into solving a mystery: how could North Korea claim that it has reprocessed all of its 8,000 rods if the one known reprocessing plant, at Yongbyon, has been operating only sporadically?

At the C.I.A. and the National Security Council, senior officials have long expressed concern that they could be missing something, that a second plant could be buried somewhere, though that would pose a number of technical challenges. Those fears have been heightened by reports from South Korean intelligence that one of its agents — whose reliability is unknown — reported the existence of a second plant, northeast of Yongbyon. 

North Korea has an estimated 11,000 to 15,000 deep underground military-industrial sites, according to one American intelligence estimate, and the nation's leadership has a history of constructing duplicate facilities for such important capabilities as tank production or command-and-communications systems.

"If you follow their logic, if we find a second reprocessing location, maybe there are more," said one American official. "It is a reasonable assessment, given North Korea's proclivity to have multiple facilities for every critical aspect of its national security infrastructure." 

Similar logic, of course, led the American intelligence agencies to some of their conclusions about Iraq. But North Korea has a far more sophisticated nuclear program, built over the years with the help first of China and Russia, and in the case of uranium production, Pakistan. 

China has now become fully engaged in trying to come up with a diplomatic solution that would not cause chaos on its border with North Korea, or an influx of refugees. A senior Chinese official, Deputy Foreign Minister Dai Bingguo, who has long experience with North Korea, spent an unusually long time — two and half hours — meeting with Secretary of State Colin L. Powell and other American officials on Friday. He also saw Condoleezza Rice, the national security adviser, and Vice President Dick Cheney.

The issue is the administration's demand that South Korea and Japan be part of any negotiations with North Korea, which wants to deal only with the United States. 

But some administration officials, especially at the Pentagon, believe that negotiations, while necessary, will ultimately prove fruitless. They do not believe that North Korea will ever trade away all of its nuclear program, the only card the starving country has to play to compel the world's attention. 

Mr. Bush has said he would not settle for another nuclear freeze, like the one Mr. Clinton approved in 1994, and he has insisted that all North Korean nuclear facilities must be dismantled. Mr. Bush has also come under increasing criticism for letting the problem fester too long as he dealt with Iraq, a view voiced by former Secretary of Defense William J. Perry this week. 

Yet it is unclear what Mr. Bush may consider if diplomacy fails. He is already organizing more intrusive inspections of ships and planes, hoping to step up economic pressure on North Korea.

But for military planners, should Mr. Bush decide that American security requires a pre-emptive attack, any confirmation of additional weapons facilities vastly complicates the work of singling out those facilities, since there may be no certainty that all of the important locations have been found. 

If any secret facilities have been operating, their production of fissile material may have already spread in small quantities to any number of other locations. The C.I.A. concluded in the early 1990's that North Korea might possess two crude weapons already, but it has never confirmed that. 

Such uncertainties remain. The worst case is that the spent fuel rods have been moved to a previously undiscovered reprocessing plant, where the plutonium has been extracted and already shipped around the nation in five- to eight-kilogram packages for weapons production.