Officials Fear Bomb Design Went to Others
WASHINGTON — Four years after Abdul Qadeer Khan, the leader of the world’s largest black market in nuclear technology, was put under house arrest and his operation declared shattered, international inspectors and Western officials are confronting a new mystery, this time over who may have received blueprints for a sophisticated and compact nuclear weapon found on his network’s computers.
Working in secret for two years, investigators have tracked the digitized blueprints to Khan computers in Switzerland, Dubai, Malaysia and Thailand. The blueprints are rapidly reproducible for creating a weapon that is relatively small and easy to hide, making it potentially attractive to terrorists.
The revelation this weekend that the Khan operation even had such a bomb blueprint underscores the questions that remain about what Dr. Khan, a Pakistani metallurgist and the father of Pakistan’s nuclear weapons program, was selling and to whom. It also raises the possibility that he may still have sensitive material.
Yet even as inspectors and intelligence officials press their investigation of Dr. Khan, officials in Pakistan have declared the scandal over and have discussed the possibility of setting him free. In recent weeks, American officials have privately warned the new government in Pakistan about the dangers of doing so.
“We’ve been very direct with them that releasing Khan could cause a world of trouble,” a senior administration official who has been involved in the effort said last week. “The problem with Pakistan these days is that you never know who is making the decision — the army, the intelligence agencies, the president or the new government.”
The illicit nuclear network run by Dr. Khan was broken up in early 2004. President Bush, eager for an intelligence victory after the failure to find unconventional weapons in Iraq, declared that ending Dr. Khan’s operation was a major coup for the United States. Since then, evidence has emerged that the network sold uranium enrichment technology to Iran, North Korea and Libya. Investigators are still pursuing leads that he may have done business with other countries.
Dr. Khan is an expert in centrifuges used to produce enriched uranium for bomb fuel, and much of the technology he sold involved enrichment. But it was only in recent months that officials have begun to confirm that they had found the electronic design for a bomb itself among material seized from some of Dr. Khan’s top lieutenants, a Swiss family, the Tinners.
The same design documents were found in computers in three other locations connected to Khan operatives, according to a senior foreign diplomat involved in the investigation.
American officials and inspectors at the International Atomic Energy Agency say they have been unable to determine if the weapon blueprints were sold to Iran or other customers of the smuggling ring.
The blueprints bear a strong resemblance to weapons tested by Pakistan a decade ago, said two senior diplomats involved in the investigation. Pakistani officials have balked at providing much information about the newly revealed warhead design, just as they have refused to allow the C.I.A. or international atomic inspectors to directly interrogate Dr. Khan, who is still considered a national hero in Pakistan for helping it become a nuclear weapons state.
Pakistani officials insist that Dr. Khan, as the leader of a uranium enrichment program, had no weapons access. But this is the second weapons design found in his smuggling network. The first was for an unwieldy but effective Chinese design from the mid-1960s that Libya acknowledged obtaining from the Khan network before it surrendered its bomb-making equipment in 2003.
Both the new and the old designs exploit the principle of implosion, in which a blast wave from a sphere of conventional explosives squeezes inward with tremendous force to compress a ball of bomb fuel, starting the chain reaction and the atomic explosion. A nuclear official in Europe familiar with the Khan investigation said the new design was powerful but miniaturized — using about half the uranium fuel of the older design to produce a greater explosive force.
“Pakistan cannot put the big China design on any of its rockets,” said the official, who spoke on the condition of anonymity because the information is classified. “It’s too big.” A smaller warhead created from the new design, he added, is “more efficient and easier to hide,” meaning that one day it might become a “terrorist issue.”
China first exploded the old design in 1966, nuclear experts say, and Pakistan fired the miniaturized version in 1998.
Nuclear experts said a warhead built from the new design was small enough to fit atop a family of medium-range missiles that derive from North Korea’s Nodong class of missiles. Those missiles include Pakistan’s Ghauri and Iran’s Shahab. All are about four feet wide, and any warhead atop them must, by definition, be smaller.
In interviews in Vienna, Islamabad and Washington, officials have said that the weapons design was far more sophisticated than the blueprints discovered in Libya in 2003, when Col. Muammar el-Qaddafi gave up his country’s nuclear weapons program. The design is electronic, they said, making it easy to copy — and they have no idea how many copies, if any, are circulating.
On Sunday, Mr. Bush’s national security adviser, Stephen J. Hadley, said that the administration remained concerned about the possibility that additional plans had been disseminated, but he did not address any of the latest revelations, which were reported Sunday by The Washington Post and The New York Times. “We’re very concerned about the A. Q. Khan network,” he told reporters traveling with Mr. Bush from Paris to London.
The existence of the compact bomb design began to become public in recent weeks after Switzerland announced that it had destroyed a huge stockpile of documents, including weapons designs, that were found in computers belonging to Friedrich Tinner and his two sons, Marco and Urs, all arrested as part of the Khan investigation.
Switzerland’s president, Pascal Couchepin, said in late May that the government had destroyed the documents to keep atomic materials from “getting into the hands of a terrorist organization or an unauthorized state.”
Two former Bush administration officials said they believed that the Tinners had provided information to the C.I.A. while the father and two sons were still working for Dr. Khan and that some of their information helped American and British officials intercept shipments of centrifuges en route to Libya in 2003.
When news of that interception became public and Libya turned its $100 million program over to American and atomic energy agency officials, President Pervez Musharraf of Pakistan forced Dr. Khan to issue a vague confession and then placed him under house arrest. Dr. Khan has since renounced that confession in Pakistani and Western news media, saying he made it only to save Pakistan greater embarrassment.
It was not until 2005 that officials of the International Atomic Energy Agency, which is based in Vienna, finally cracked the hard drives on the Khan computers recovered around the world. And as they sifted through files and images on the hard drives, investigators found tons of material — orders for equipment, names and places where the Khan network operated, even old love letters.
“There was stuff about dealing with Iranians in 2003, about how to avoid intelligence agents,” said one official who had reviewed it. But the most important document was a digitized design for a nuclear bomb, one that investigators quickly recognized as Pakistani.
“It was plain where this came from,” a senior official of the atomic energy agency said. “But the Pakistanis want to argue that the Khan case is closed, and so they have said very little.”
In public statements, Pakistani officials have insisted that the Khan “incident,” as they call it, is now history, and they publicly declared nearly two years ago that their investigations were over.
A senior Pakistani official said that in April that the information provided by the atomic energy agency was “vague and incomplete,” and he insisted that because Dr. Khan’s laboratories specialized in manufacturing equipment needed to enrich uranium, “he was not involved in weapons designs.”
But atomic energy agency investigators and American intelligence officials say they have little doubt that he was the source of the digitized bomb design. “Clearly, someone had tried to modernize it, to improve the electronics,” one said. “There were handwritten references to the electronics, and the question is, who was working on this?”
The officials said that parts of the design were coded so that they could be transferred quickly to an automated manufacturing system.
David E. Sanger reported from Washington, and William J. Broad from New York. Steven Lee Myers contributed reporting from London.