The Security Council had been waiting for a UN report at the end of the month on Iran's nuclear intentions, before deciding on further measures. But after Mahmoud Ahmadinejad's triumphal announcement yesterday - accompanied by chants of "Death to America", "Death to Israel" and "Death to Counter-Revolutionaries" - some UN members were drawing their own conclusions.
Not for the first time, US diplomats found themselves grateful that President Ahmadinejad had made the work of persuading other UN members of Tehran's intentions so much easier. "I can't imagine anyone would be pleased by such a blatant disregard of what the council has asked for," the official said.
However, the findings of the report by the International Atomic Energy Agency (IAEA) are not a foregone conclusion. The speed with which Iran has moved has surprised some experts, and it is possible that the Iranian leader was grandstanding for political reasons. Whatever the reality at the enrichment facility in Natanz, though, the Iranian leadership has shown it is in no mood to comply.
If the IAEA report is overwhelmingly negative, the immediate goal of the US, with the support of British, French and German diplomats, is to turn up the international pressure on Iran while maintaining a consensus among the major powers as long as possible. The American official said that the US delegation would wait until the IAEA director, Mohamed ElBaradei, reports on Iranian compliance with a Security Council demand that it suspend uranium enrichment and open its nuclear facilities to international inspection.
That demand was non-binding, essentially a political request. The next step for the US and its allies will be to seek a binding resolution, possibly under chapter seven of the UN charter, which deals with threats to international peace and security.
Such a resolution would be intended to put international legal pressure on Iran, rather than as an immediate preface to military action. Nevertheless Russia and China have shown themselves reluctant to give their agreement, fearing it could be used in future to justify an attack on Iran.
The negotiations over the next step are likely to be long and heated, particularly as they will be played out against a backdrop of reports of US military planning. Russia and China may agree to abstain in a vote on a resolution, but if not, the US has made it clear it will go it alone with bilateral sanctions. Earlier this week, Javier Solana, the European Union foreign policy chief, said the EU would consider its own sanctions, perhaps restricting European visas to Iranian officials. Another possibility is the withholding of credit guarantees for private companies dealing with Iran. After the sanctions stage, however, the unity between the US and Europe is likely to break down. Mr Solana said: "Any military action is absolutely [off] the table for us."
The Bush administration refuses to rule out the use of force and the recent press reports about military planning for possible air strikes could have been deliberately linked for psychological effect.
Guardian Unlimited © Guardian Newspapers Limited 2006