U.S.: Documents hint at Iranian nuclear test

WASHINGTON — Iranian engineers have completed sophisticated drawings of a deep subterranean shaft, according to officials who have examined classified documents in the hands of U.S. intelligence for more than 20 months.

Plans for the 400-meter tunnel appear designed for an underground atomic-test detonation that one day might announce Iran's arrival as a nuclear power, the officials said.

By U.S. and allied intelligence estimates, that day remains as much as a decade away — assuming Iran applies the full measure of its resources to the project and encounters no major technical hurdles. But whether Iran's leaders have reached that decision and what concrete progress the effort has made remain divisive questions among government analysts and U.N. inspectors.

Drawings of the unbuilt test site appear to U.S. officials to signal at least the ambition to test a nuclear explosive. But U.S. and U.N. experts said the undated drawings do not fit into a larger picture clearly. Nowhere, for example, does the word "nuclear" appear. Authorship is unknown, and there is no evidence of an associated program to acquire, assemble and construct components of such a site.

"The diagram is consistent with a nuclear test-site schematic," one senior U.S. source said, noting that the drawings envision a test-control team parked a safe six miles from the shaft. As far as U.S. intelligence knows, the idea has not left the drawing board.

Other suggestive evidence is cloaked in similar uncertainty. Contained in a laptop stolen by an Iranian citizen in 2004 are designs by a firm called Kimeya Madon for a small-scale facility to produce uranium gas, the construction of which would give Iran a secret stock that could be enriched for fuel or for bombs. Also on the laptop — obtained by U.S. intelligence — were drawings on modifying Iran's ballistic missiles in ways that might accommodate a nuclear warhead. Beyond the computer files, an imprisoned Pakistani arms dealer recently offered uncorroborated statements that Iran received several advanced centrifuges, equipment that vastly would improve its nuclear knowledge.

U.S. intelligence considers the laptop documents authentic but cannot prove it. Analysts cannot rule out the possibility that internal opponents of the Iranian leadership could have forged them, or that the documents were planted by Iran to convince the West that its program is at an immature stage.

CIA analysts, some involved on the flawed assessments of Iraq's weapons programs, initially speculated a third country, such as Israel, might have fabricated the evidence. But that theory has been dropped.

British intelligence, asked for a second opinion, concurred last year that the documents appear authentic. German and French officials consider the information troubling, sources said, but Russian experts have dismissed it as inconclusive. IAEA inspectors, who were highly skeptical of U.S. intelligence on Iraq, have begun to pursue aspects of the laptop information that appear to bolster previous leads.

"There is always a chance this could be the biggest scam perpetrated on U.S. intelligence," one U.S. source acknowledged. "But it's such a large body of documents and such strong indications of nuclear-weapons intent, and nothing seems so inconsistent."

Bush administration officials, convinced that Iran has a weapons program, believe that the body of documentation is the nearest anyone can expect to "smoking gun" evidence. Even in the U.S. government, though, the predominant interpretation is more complex. And any step toward uranium enrichment, experts said, is consistent with three competing explanations — that Iran's program is peaceful, that it aims for a weapon or that options are being kept open.

Mohamed ElBaradei, director general of the IAEA, said he cannot judge Iran's program "exclusively peaceful." At the same time, Iran is "not an imminent threat," he said.

Until Iran operates an industrial-scale centrifuge cascade for the production of bomb-grade uranium, the country will remain as much as 10 years away from a weapon, say U.S. intelligence experts.

Those experts have said that none of the drawings — for the test shaft, the conversion facility or Iran's missile program — alters those projections.

That assessment, by an intelligence community determined not to repeat the embarrassments of Iraq, is more conservative than views of some policymakers. Some within the Bush administration suggest that the CIA is demanding an unrealistically high standard of evidence before reaching conclusions that the White House believes are obvious.

"I just don't have a lot of confidence in the assessments," said a senior administration official who helped craft the White House's use of intelligence on Iraqi weapons programs.