WASHINGTON – After nearly 1,000 days of stop-and-go negotiations, Europe and America may finally ask the U.N. Security Council to weigh in on Iran’s nuclear program.

Yesterday a White House spokesman, Scott McClellan, called Iran’s decision to remove U.N. seals from uranium enrichment facilities at Natanz a “serious miscalculation.” Meanwhile, Prime Minister Blair said it was likely Iran’s violations would now be referred to the U.N. Security Council. Two diplomatic officials here said America and Britain are preparing the text of a resolution to refer the Iranian program to the United Nations, a move that could result at least in international censure and possibly in sanctions and other penalties.

Since June 2003, Britain, France, and Germany have negotiated with Iran through the International Atomic Energy Agency, a body unable to either declare war or authorize economic sanctions. Thus far, the Islamic Republic has escaped censure and sanctions by the U.N. Security Council. Although Iran has given negotiators incomplete information regarding its nuclear program and denied access to IAEA inspectors in 2003 and 2004, the European three have agreed to a series of extensions that have kept the matter of Iran’s nuclear program inside the IAEA. The latest gambit for the West has been a Russian initiative that would allow Iran to have nuclear fuel, but only if were enriched in Russia. Iran last month rejected that offer. Earlier this month, the Iranians announced they had mastered new technology to derive uranium from uranium ore.The country’s decision to break the seals on research equipment Tuesday may be the final straw for the West.

“They have time after time defied the will of the international community,” a State Department spokesman, Sean McCormack said yesterday, noting that Iran has rejected numerous requests for information from the IAEA and the European three. “They have replied with silence or obfuscation or deception on those issues. So I think we are fast approaching a decision point on what diplomatic next steps the international community is going to be taking,” Mr. McCormack said.

Speaking to reporters yesterday, Mr. Blair, who has been in touch with his German counterpart, said, “I think the first thing to do is to secure agreement for a reference to the Security Council, that is indeed what the allies jointly decide as I think seems likely.”

“Obviously we don’t rule anything out.” Mr. Blair said, echoing the rhetoric of President Bush.

Mr. Blair’s words are important in light of the role he played in persuading Mr. Bush in 2003 to pursue the European-led negotiations. Some American diplomats then believed there were enough votes inside the IAEA for a referral to the council, but the push was called off at the last minute to move ahead with talks.

Mr. Blair is not the only European official to express concern over Iran’s behavior. Yesterday Italy’s foreign minister, Gianfranco Fini, said, “Iran’s determination to pursue its nuclear program outside the boundaries of agreed deals is a motive for constant, deep concern.”

In 2003 Iran admitted to operating a hitherto secret enrichment program. In exchange for leniency from the IAEA, the Iranians tentatively agreed to allow unannounced inspections of those facilities. But the inspectors often found sites doctored before they arrived or their mission blocked. In one case, a military research facility was found burned to the ground after its contents were moved to another building.

Despite this pattern, Britain, France, and Germany have been reluctant to escalate tensions with Iran, perhaps due to the hefty trade the countries conduct with the Islamic Republic. But a cautious approach now looks untenable. As Iran has grown more defiant on the nuclear front, President Ahmadinejad’s rhetoric against Jews and Israel has become more rabid. In October at a conference dedicated to ending Zionism, Mr.Ahmadinejad said he wished to “wipe Israel off the map.” In recent weeks the Iranian president has repeated his view that the Holocaust never happened.

In December the German press reported America was briefing NATO allies for a possible unilateral strike on Iran’s nuclear facilities. In particular, a story in Der Spiegel said Germany’s director of central intelligence, Porter Goss, briefed Turkish leaders on the Iranian program and discussed such a move. The story has yet to be confirmed.