The United Nations nuclear watchdog agency is investigating potential links between the atomic programs of Iran and Pakistan after discovering that the secret Iranian uranium-enrichment program used technology identical to Pakistani plans, diplomats said.
Tehran acknowledged to the International Atomic Energy Agency that its centrifuge enrichment program was based on designs by a European firm, Urenco. Diplomats said the designs were the same Urenco-based technology used by Pakistan to develop its nuclear bomb in the 1990s.
Centrifuges are used to process uranium into fuel for reactors or fissile material for bombs. The purification process is complex, and perfecting the machines, which spin at twice the speed of sound, can take years.
The most recent IAEA report on Iran's nuclear program said Tehran started research in 1985 and got the centrifuge designs "from a foreign intermediary in 1987." Iran has told the agency that they came from a middleman whose identity remains a mystery.
The United States has accused Iran of using a civilian program to conceal efforts to develop an atomic bomb. IAEA inspections in recent months have uncovered numerous instances in which Iran concealed nuclear activities that could have played a role in developing an atomic bomb.
Iran has maintained that its nuclear program exists solely to generate electricity. This month, Tehran agreed to provide the IAEA with a full disclosure of its program's history and accept tougher IAEA inspections of its nuclear facilities.
On Wednesday, the IAEA governing board in Vienna condemned Iran for its long cover-up of sensitive nuclear research and warned that any future violation of its nonproliferation obligations could result in sanctions.
The board stopped short of referring Iran to the U.N. Security Council for possible sanctions, as the Bush administration initially wanted.
A Western diplomat said in a telephone interview Thursday that the U.S. believed that Iran was still hiding activities and that the matter eventually would go to the U.N.
Mohamed ElBaradei, director-general of the IAEA, said a new report on Iran would be ready for the agency's board in mid-February. He said the agency's inspectors had "a lot of work to do before we can conclude that Iran's program is exclusively for peaceful purposes."
Diplomats said discovering the origins of the Iranian uranium enrichment process was one of the key areas under investigation by the IAEA as it attempted to reconstruct 18 years of hidden activities.
A diplomat said that the IAEA had not determined whether the centrifuge plans had come directly from Pakistan or were obtained or stolen from a Pakistani nuclear laboratory by the middleman.
Urenco is a British, Dutch and German consortium and a world leader in centrifuge design and operation. The company denied supplying centrifuge technology or blueprints to Iran.
Pakistan repeatedly has denied providing any nuclear assistance to Iran and criticized as "anti-Muslim" articles suggesting it had aided Iran. Tehran also has denied cooperating with Pakistan.
Abdul Qadeer Khan, the primary developer of Pakistan's nuclear bomb, worked at the Urenco enrichment plant in the Dutch city of Almelo in the 1970s. After returning to Pakistan, he was accused of stealing centrifuge plans from the facility.
Two former Iranian diplomats told the Los Angeles Times last summer that Khan made several trips to Iran, beginning in 1987, to help with Iran's nuclear program. One of them, Ali Akbar Omid Mehr, said Khan was given a villa on the Caspian Sea in return for his assistance.
On a trip to South Korea this month, Pakistani President Pervez Musharraf said a reported visit by Khan to Iran was connected with attempts to purchase short-range missiles, not nuclear technology sales.
The Iranian centrifuge program is at the top of the IAEA inquiry list because traces of weapons-grade uranium were found in two locations where the machines had been assembled and tested.
One of the locations was the massive underground enrichment plant being constructed near Natanz in central Iran. Diplomats said IAEA inspectors spotted the similarity to the Urenco designs when they visited the plant.
The centrifuges at Natanz appeared to have been modified to produce enriched uranium more efficiently that the original design, said diplomats familiar with the inspection.
Traces of weapons-grade uranium also were discovered at Kalaye Electric Co. Tehran reluctantly acknowledged having performed extensive tests on purifying uranium with centrifuges at the Kalaye plant, once identified as a watch factory.
The machinery had been removed and extensive construction had been done by the time inspectors visited the site, but they found the enriched-uranium particles through tests.
Iran had long maintained that its centrifuge program was indigenous.
Confronted with the IAEA discoveries, Iranian officials said some components were contaminated with enriched uranium when they were purchased outside the country through middlemen.
The inquiry into the origins of the centrifuge designs is only one aspect of a widespread investigation by the IAEA of what turned out to be a surprisingly broad nuclear program in Iran.
The IAEA report this month said Iran had been conducting research using exotic laser technology to enrich uranium for 12 years before disclosing the program this fall. Some of the laser technology appears to have come from Russia and some of it may have European origins, diplomats familiar with the inquiry said.
The agency's report said Iran established a pilot plant for laser enrichment three years ago and shut it down and disassembled the machinery in May.