The United States said Tuesday Iran's move to reopen previously sealed nuclear sites represents a "major escalation" of the diplomatic confrontation over its nuclear intentions. U.S. officials say the action has triggered intense diplomacy among permanent U.N. Security Council members and other concerned parties about how to respond.
In coordinated statements, both the White House and State Department called the latest Iranian moves a serious escalation of the dispute over its nuclear program.
They said the United States is consulting with other concerned governments about what to do next, including the possible calling of an emergency session of the International Atomic Energy Agency governing board.
At a news briefing, State Department Spokesman Sean McCormack cited similar statements of alarm from others including key European Union governments who have been trying for years to negotiate a solution that could ease global concern about Iran's nuclear intentions.
He said by spurning diplomatic overtures from the EU Three - Britain, France and Germany - as well as a parallel effort by Russia - Iran is isolating itself, and that its statement that it wants to enrich a limited amount of uranium for research has no credibility:
"They call it research and development." said Sean McCormack. "They call it a small program. Well, when it comes to enrichment technology, there are no small programs concerning Iran. Because what they want to do - they want to develop the expertise in enriching uranium so they can produce the fissile material that would allow them to build a nuclear weapon."
The spokesman said what the Iranians are essentially asking the world community to do is trust them when they say their enrichment plans are limited.
However, he said given Iran's "history of deception" on the issue, and a recent series of "alarming" statements by Iranian President Mahmoud Ahmadinejad, international trust has eroded to the point of being non-existent.
He said for concerned governments not to consider what the next steps in the confrontation might be would be irresponsible.
A senior official who spoke to reporters here said convening an emergency meeting of the International Atomic Energy Agency on the issue is a live option.
The IAEA governors found Iran to be in non-compliance with its Nuclear Non-Proliferation Treaty obligations at a meeting in October, but put off punitive action pending further diplomacy.
U.S. officials say they are confident there are enough votes in the 35-nation IAEA governing board to refer the matter to the U.N. Security Council for possible sanctions against Iran.
Sanctions action would require the support of all five permanent Security Council members, and Bush administration officials are making no predictions about a possible vote there.
But they are encouraged by what they say is a growing consensus about the danger of Iran acquiring a nuclear weapons capability.
In recent days, all five permanent council members, including Russia and China, have sent Iran similar messages urging Tehran not to follow through with threats to resume nuclear activities, and return to negotiations.
Spokesman McCormack said Secretary of State Condoleezza Rice spoke by telephone Tuesday with Russian Foreign Minister Sergei Lavrov, whose government has offered to enrich uranium for Iran to satisfy Tehran's stated need for a nuclear-electric generating capacity.
U.S. officials have said that Iran's expressed desire for a complete nuclear fuel cycle is inexplicable given its oil and gas wealth, and they have long maintained that its nominally peaceful nuclear program conceals a long-running secret weapons development effort.