The British, French and German foreign ministers said Thursday that negotiations with Iran over its nuclear program had reached a "dead end" and the Islamic republic should be referred to the U.N. Security Council.

U.N. Secretary-General Kofi Annan said later Thursday that Iran's top nuclear negotiator, Ali Larijani, told him that Tehran was interested in "serious and constructive negotiations" with the European countries over its atomic program but it favored a deadline.

"He affirmed to me that they are interested in serious and constructive negotiations but within a timeframe, indicating that the last time they did it for 2 1/2 years and no result," Annan told reporters.

The British, French and German ministers did not specify what action should be taken by the Security Council, which could impose sanctions. However, French diplomats refused to discuss potential options and bristled at the talk of sanctions, saying they were not that stage.

The ministers called for a special session of the International Atomic Energy Agency to decide the referral.

The action came two days after Iran broke U.N. seals at a uranium enrichment plant and said it was resuming nuclear research after a two-year freeze.

Enriched uranium can be used as a fuel for both nuclear energy and nuclear weapons. Iran says its nuclear program is only for fuel.

In Washington, Secretary of State Condoleezza Rice, coordinating with European allies, called on the United Nations to confront Iran's "defiance" and demand that Tehran halt its nuclear program. She said she was "gravely concerned" by Iran's secret operations.

Rice declined to say whether the United States has the necessary votes in the Security Council to punish Iran. But she said, "It is very clear that everyone believes a very important threshold has been cleared."

In a joint statement, the diplomats cited Iran's "documented record of concealment and deception" and charged that its government seems "intent on turning its back on better relations with the international community."

"From our point of view, the time has come for the U.N. Security Council to become involved," German Foreign Minister Frank-Walter Steinmeier said after meeting with his French and British counterparts and the European Union's foreign policy chief, Javier Solana.

Iranian state radio and television did not initially report the European decision, but later the television broadcast part of the Berlin press conference with comments by the British and German foreign ministers.

"All Iranians are united in pursuing the nuclear program," the newscaster added.

Nuclear proliferation expert Francois Gere, who heads the French Institute of Strategic Analysis, said there are few, if any, viable options for punishing Iran — and the Iranians know that. The French, therefore, are still hoping for a diplomatic way out.

"There is absolutely no discussion of punishment for the moment in the French approach," Gere said.

Oil sanctions would be double-edged and likely would affect oil and gas prices, he said.

The Bush administration, meanwhile, arranged to have Undersecretary of State Nicholas Burns go to Britain, France and Germany next week to coordinate strategy. Burns also will hold talks in India, said a senior U.S. official who spoke on condition of anonymity because the State Department was not ready to issue a formal statement.

While Burns will be consulting in Europe, Solana plans to be in Washington to coordinate with Bush administration officials.

Steinmeier said the three countries would inform the board "that our talks with Iran have reached a dead end."

Solana said the EU and national governments were left with no choice but to call for Iran's referral. But he would not rule out a new round of negotiations with Tehran.

Steinmeier stressed that the Europeans remain ready to solve the problem "diplomatically, multilaterally and by peaceful means."

Iran's president, Mahmoud Ahmadinejad, has vowed to press ahead with a nuclear program that Iran says is designed to produce civilian energy.

"Unfortunately, a group of bullies allows itself to deprive nations of their legal and natural rights," he said Wednesday. "I tell those superpowers that, with strength and prudence, Iran will pave the way to achieving peaceful nuclear energy.

Iran's move increased worries in the United States and other Western countries that Iran intends to produce nuclear weapons, while Russia, a longtime Iran ally, indicated it could reverse its opposition to bringing Tehran before the Security Council, which could impose sanctions.

Russia and China, both members of the IAEA board that would have to approve referring Iran to the Security Council, have previously opposed the idea.

Russian Foreign Minister Sergey Lavrov said Russia, the United States, the European Union and China would discuss the issue in London next week.

He told Ekho Moskvy radio that Iran's latest move did not violate international law — but also said Moscow did not exclude the possibility of turning the Iranian dossier over to the Security Council.

"It causes concern that Iran is opting out of its moratorium in the absence of answers to questions, serious questions" from the IAEA, Lavrov said. "Our main task is to persuade Tehran through joint efforts to return to the moratorium."

China on Thursday urged more talks, without saying whether it would back taking Tehran to the Security Council.

China "hopes that all parties concerned can exercise restraint and resolve this within the IAEA framework and through peaceful negotiations," Foreign Ministry spokesman Kong Quan said in Beijing. "We firmly believe this serves the interests of all parties concerned."

The Security Council in recent years has moved toward imposing targeted measures — such as arms embargoes against countries and rebel groups, travel bans and asset freezes — that minimally impact the general population. Blanket sanctions imposed on Iraq after its 1990 invasion of Kuwait seriously affected the entire population.

However, enforcement of U.N. sanctions has proven very difficult in many countries.

In the case of Iran, the Security Council likely would increase the pressure gradually, starting with a condemnation and demanding that Iran comply with IAEA decisions. If Iran did not respond positively, Western envoys almost certainly would push for further measures, a code word for sanctions, or at minimum threaten them.