VIENNA (Reuters) -- UN inspectors have revisited Iran's second uranium-enrichment facility, diplomats said, after voicing concern that Tehran's belated disclosure of the nuclear site meant more may be hidden away.
The inspectors aimed to make further checks of the Fordow site's layout and wanted more Iranian explanations to pinpoint the project's chronology and original purpose, as well as access to its director and designers.
Iran revealed the site to the International Atomic Energy Agency (IAEA) in September, two years after it said construction began. The IAEA said Iran was legally bound to own up about the plant as soon as plans were drafted. Iran disputes this.
An IAEA report on November 16 said the UN watchdog's inspectors' first visit to the site last month did not yield all the information they needed to verify its purpose from the beginning was peaceful -- that is, churning out low-enriched uranium for electricity generation, rather than high-enriched material for atomic bombs.
The report also said Iran's tardy disclosure "reduces confidence" in the absence of further undeclared sites.
A senior Iranian envoy told Reuters on November 17 that Iran hatched the bunkered Fordow site to preserve enrichment work in case its larger Natanz enrichment complex were bombed. He called Fordow a "political message" that neither sanctions nor possible military assault would ever cripple Tehran's nuclear program.
But Ali Asghar Soltanieh, Iran's ambassador to the IAEA, said suspicions it had more nuclear production sites squirreled away were wrong and unfair, and it was living up to transparency commitments to the IAEA.
Western analysts said Fordow, due for start-up in 2011, could not have run without support sites since Tehran's one known uranium-processing center at Isfahan serves Natanz and would be targeted in any air strikes.
Iran's arch-foe Israel has hinted at last-ditch military action should diplomacy to rein in Iran's nuclear campaign fail.
Iran Challenges IAEA's Writ
Soltanieh told reporters in Vienna on November 18 that inspectors would return to Fordow, tucked away beneath a mountain, on Thursday to show "we are being very transparent and cooperative, in accordance with our obligations".
The IAEA would have regular access to Fordow from now on, he said. But he rejected the UN watchdog's request for written assurances of no more sites being built or planned now as "without legal justification."
He said Iran's 1970s safeguards pact with the agency required it solely to notify the IAEA of a new plant within six months of nuclear material being introduced to such a facility.
The IAEA says Iran, along with many other member states, adopted a tightened transparency code in 2003 mandating notice of nuclear plans as soon as they are drawn up.
Iran unilaterally reverted to the old rule in 2007 in protest at UN sanctions it calls illegal.
Western diplomats said Iran came clean on the Fordow site to the IAEA in September only after learning that U.S., French, and British spy services had discovered it and Western leaders were about to blow the whistle.
Western nuclear analysts say Fordow's small capacity makes it unsuitable for any purpose but to enrich smaller quantities of uranium suitable for a bomb, which they believe Tehran would have done had the site remained clandestine.
Western suspicions rest on Iran's history of nuclear secrecy and restricting IAEA inspections and access for investigations.
"Iran almost certainly has additional unreported nuclear facilities. Fordow doesn't make sense otherwise. Iran's own stated logic implies that they would have a second uranium-conversion plant, as a backup in case the Isfahan plant is bombed," said Mark Fitzpatrick, chief proliferation analyst at London's International Institute for Strategic Studies.