UNITED NATIONS, May 2 -- The Bush administration said Monday that Iran was trying to build atomic weapons in secret and suggested the international community should respond by taking away Tehran's right to nuclear energy technology.
Other world leaders attending a nuclear conference seemed to dismiss the U.S. call for punitive measures. Instead, they spoke of incentives and negotiations as a way of encouraging the Islamic republic to give up worrisome aspects of its energy program that could be diverted for weapons work.
The Bush administration went into the conference hoping to increase pressure on Iran, but its speech highlighted the differences between the United States and its allies over how best to handle emerging nuclear issues.
The crises in Iran and North Korea took center stage on the opening day of a month-long conference to review and possibly strengthen the nuclear Non-Proliferation Treaty. Written in 1970, the treaty provides countries that forgo nuclear weapons with access to sensitive technology to be used only for nuclear energy. As part of the deal, the five original weapons states -- the United States, France, Britain, Russia and China -- agreed to eventually eliminate their own stockpiles.
The treaty is credited with reducing the spread of nuclear weapons, but it has come under enormous strain in recent years with the discovery of a nuclear black market and a decision two years ago by North Korea to walk away from the agreement. India, Pakistan and Israel never signed the deal, and North Korea now says it has nuclear weapons.
The discovery of secret nuclear facilities in Iran two years ago fueled suspicions it was using its nuclear energy program as a cover for weapons work. So far, international inspectors have found no proof of a bomb program in Iran, which denies it intends to build nuclear weapons. But the top U.S. representative to the conference rejected both the findings of the inspectors and Iran's position.
"For almost two decades, Iran has conducted a clandestine nuclear weapons program," said Assistant Secretary of State Stephen G. Rademaker. He said Iran had failed to live up to its obligations under the treaty and that "no state in violation" of its main articles should receive its benefits.
Iran, which sent a high-level delegation to the conference led by Foreign Minister Kamal Kharrazi, was planning a tough response Tuesday. Kharrazi met privately Monday with German Foreign Minister Joschka Fischer and with Mohamed ElBaradei, director general of the International Atomic Energy Agency, which is leading the inquiry in Iran.
The Islamic republic has been engaged in two years of negotiations with Germany, France and Britain over the future of its nuclear energy program. The negotiations are guided by an agreement that Europe would offer Iran incentives in exchange for guarantees that the nuclear program is peaceful. But after a difficult round of talks last weekend, Iranian officials threatened to resume some nuclear work unless the European nations demonstrate progress in the negotiations.
Kharrazi would not say which way the Iranians would go. "That depends on the decision of our leaders," he said.
ElBaradei urged Iran not to make any unilateral decisions, but he acknowledged that the process between Iran and the Europeans is at "a delicate phase. There's no question about it."
Fischer said it has been "a difficult negotiation, but the challenge is an important one." He said he hopes the Iranians will avoid any resumption of nuclear work while the negotiations are continuing. "We want to reach a success."
Fischer did not accuse Iran of secretly working toward nuclear weapons and said the negotiations are aimed at achieving a permanent cessation of the more sensitive aspects of its program.
Rademaker called for complete dismantlement of those components in a speech that focused heavily on Iran, mentioning the country 10 times. North Korea was mentioned half as often.
"The assertion that Iran is making nuclear weapons hasn't been backed up by direct evidence," said Daryl G. Kimball, director of the Arms Control Association in Washington. "And the conference isn't going to endorse the plan Rademaker laid out when Iran and the Europeans are engaged in discussions about the program."
Over the next four weeks delegates will discuss suggestions to limit the spread of nuclear weapons and technology. There is little agreement on most issues, including the conference agenda.
U.N. Secretary General Kofi Annan suggested the delegates "create incentives for states to voluntarily forgo the development" of nuclear energy programs that rely on sensitive technologies. And he called on the United States and Russia to move quickly toward reducing the thousands of nuclear weapons in their own stockpiles.
"The use of security assurances would also help to reduce security concerns," ElBaradei told the conference as a reminder that countries such as Iran are more likely to keep their nuclear options open if they feel threatened.