Rice, at a news conference, declined to say whether the United States has the necessary votes at the U.N. Security Council to punish Iran — or would even try at this stage.
But she said impatience with Iran was growing and that Tehran was out of step with advances in democracy in the region. And she repeated that she believes there are enough votes for the International Atomic Energy Agency, the U.N. agency that monitors nuclear activity, to refer the issue to the Security Council.
"I don’t think it serves anybody’s purpose to have a nuclear-armed Iran," Rice said.
Rejecting Iran’s claims that its nuclear program was not designed to produce waapons, Rice said, "I don’t think anybody believes Iran’s protestations that this is a peaceful program."
Pending coordination with the European allies, Rice did not spell out specific measures against Iran that the Bush administration might endorse or propose.
But she said she was "gravely concerned" about Iran’s secret operations and "its dangerous defiance of the entire international community."
"We have to look hard at how a strong message is sent," Rice said.
Earlier, Britain, France and Germany agreed the dispute should be referred to the Security Council by the International Atomic Energy Agency. But it has remained unclear whether China or Russia might use their veto powers to thwart Security Council action, or whether there are enough votes at the council for it to impose sanctions of some sort.
"We are not yet ready to talk about specific measures" to take against Iran, Rice said.
She said she hoped Tehran would take note of the unity around the world and act on the program. Rice cited Russia’s unhappiness with Iran as an example.
"It is very clear that everyone believes a very important threshold has been cleared," she said.
At a minimum, the Bush administration wants Iran to resume negotiations with the European Union.
Undersecretary of State Nicholas Burns will go to London next week to coordinate strategy with the allies and Undersecretary of State Robert Joseph will travel to Vienna, the headquarters of the U.N. monitoring agency, Rice said. Chinese and Russian diplomats are also expected to attend as well, said a senior U.S. official who was not authorized to make a formal announcement.
The European Union, meanwhile, will send its senior diplomat, Javier Solana, to Washington for consultations.
The Security Council could try to punish Iran with economic or political sanctions on the grounds it is proceeding secretly to develop nuclear weapons. However, that move could be blocked by a veto, a power that China and Russia share with the United States, Britain and France.
The Council imposed blanket sanctions on Iraq after its 1990 invasion of Kuwait. In the case of Iran, it could start with a demand that Iran negotiate to end its program, and ratchet it up from there.
Rice, meanwhile, rejected any comparison to the U.S. dispute with Iraq when it was ruled by Saddam Hussein, who was overthrown in a U.S.-led war. "The situations are very, very different," she said.
Iran’s president, Mahmoud Ahmadinejad, has vowed to press ahead with a nuclear program that Iran says is designed to produce civilian energy.
"This is really an Iranian regime that is digging into isolation," Rice said. "The Iranian people frankly deserve better."