WASHINGTON - The United States said it would be "concerned" by Iran's acquisition of any new nuclear technology, signalling opposition to a reported European offer to give Tehran a light-water reactor it proves it is not secretly developing atomic weapons.
The State Department said the transfer of such technology would be problematic given Iran's past performance and failure to comply with international demands to come clean on details of its nuclear program, which the United States maintains is a cover for acquiring atomic arms.
"We have long had concerns about Iran's acquisition of nuclear capability, of nuclear technology, because for many years we have seen a confirmed pattern of noncompliance with safeguards," spokesman Richard Boucher told reporters.
"We have seen the use of nuclear exchanges, nuclear technology, in order to develop what we can only describe as a nuclear weapons program and therefore we have been concerned and would remain concerned about Iran acquiring new capability in nuclear technology areas," he said.
"We fundamentally have concerns about Iran acquiring more nuclear technology and capability."
Boucher repeatedly refused to comment on the reported details of the European proposal, but acknowledged that the United States was aware of the contents of the offer, the proponents of which -- Britain, France and Germany -- are to present to Iran on Thursday.
However, according to a document obtained by AFP on Tuesday, Britain, France and Germany -- the so-called "EU3" -- the offer includes a joint promise to provide Iran with nuclear technology, including light-water nuclear reactor, if the Islamic republic complies with demands from the International Atomic Energy Agency (IAEA).
The EU3 shared specifics of its incentive package with the United States and other members of the Group of Eight (G8) industrialized nations at a meeting last week in Washington.
US officials have not taken a formal position on the offer, saying it is a matter for the EU3 and Iran to consider but raised no objection to the package being presented and, until Boucher's comments on Wednesday, appeared willing to sign off on it.
Boucher insisted the United States was not rejecting any proposals but stressed that Washington had nothing to do with the offer.
"We haven't bought on, signed on or endorsed it, but we know they're going to do it," he said.
Thursday's meeting, at IAEA headquarters in Vienna, is aimed at giving Iran a last-chance to come clean and to agree to suspend all activities related to uranium enrichment before the agency's governing board meets next month to decide whether Iran is in compliance or not.
The United States wants the IAEA, which has been investigating the US accusations of Iran's secret nuclear weapons program since February 2003, to send Iran to the UN Security Council for possible sanctions. Iran vehemently denies the US charges and has warned against such a referral.
To date, the EU3 have opposed taking the matter to the United Nations, favoring instead a policy of "constructive engagement" to get Tehran to cooperate.
But Washington has held firm to its stance and Boucher reiterated it again on Wednesday.
"Iran has shown, unfortunately, no sign of compliance with the requirements of the (IAEA) Board of Governors," he said.
"They have shown a long-term effort not to comply with the requirements of the safeguards and other agreements and therefore they need to be referred to the UN Security Council."
A Vienna-based western diplomat said the United States is watching the EU3 initiative to see how Iran responds and would afterward reconvene the G8 nations, which include Britain, Canada, France, Germany, Italy, Japan, Russia and the United States, for further discussion.
If Iran does not agree and does not comply with its obligations, the EU3 would join the United States in calling for the Islamic Republic to be taken to the Security Council, the document said.
But, if Iran does comply, the EU3 would be ready to offer a whole range of measures, including access to nuclear fuel for its civilian reactors and recognizing Iran's right "to develop a nuclear power generation program to reduce its dependence on oil and gas," it said.
The latter would also appear to clash with Washington's strong belief that Iran, with its vast petroleum reserves, has no need for atomic energy plants.
"We don't see the economic or any other rationale for a country like Iran to try to generate power with nuclear energy, given that ... they flare off way more gas every year than they could get energy from nuclear power plants of the kind that they're talking about," Boucher said.