Updated

In Tehran (search) and here on the world stage, an emphatic Iran said Tuesday it will press on with its uranium-enrichment technology, a program that has drawn Washington's fire and ratcheted up global nuclear tensions.

On the second day of a nonproliferation conference, Iran's Foreign Minister Kamal Kharrazi (search) said his country is "determined to pursue all legal areas of nuclear technology, including enrichment, exclusively for peaceful purposes."

In Iran's capital, a government spokesman said nuclear activities suspended during talks with European negotiators would be resumed, but not enrichment itself — the processing of uranium gas through centrifuges to produce either fuel for nuclear power or the stuff of atom bombs.

At Monday's opening of the U.N. conference on the Nuclear Nonproliferation Treaty (search), the U.S. delegation reiterated Washington's demand that Tehran shut down and dismantle its enrichment program, which the Americans contend is a cover for weapons development.

Kharrazi responded Tuesday that his government, in negotiation with Germany, France and Britain, "has been eager to offer assurances and guarantees that [Iran's nuclear plans] remain permanently peaceful."

But "no one should be under the illusion," he said, that such guarantees will include an end to "legal activity" under the nonproliferation treaty, which says member states have a right to develop civilian nuclear energy.

Later Tuesday in Washington, U.S. Secretary of State Condoleezza Rice said that despite the Iranian moves the United States remains committed to the European-led effort to ensure that Iran does not build a bomb.

"We continue to believe this is the only way for Iran to resolve this issue in a way that the international community will be able to verify and to support, so we very much hope that the talks are going to be successful," Rice said.

The Iranian foreign minister also made his own demands on Washington, saying the United States and other nuclear weapons states should enter into legally binding commitments not to use nuclear weapons on nonweapons states like Iran.

The big powers' nuclear arms "are the major sources of threat to global peace and security," Kharrazi said.

Other delegates also called for such commitments, known as "negative security assurances."

"Negative security assurances will strengthen security for all and buttress the nuclear nonproliferation regime," Algeria's Hocine Meghlaoui told the gathering of more than 180 nations.

The United States has long opposed a treaty prohibiting such use of nuclear weapons, and U.S. delegation spokesman Richard Grenell said Tuesday the terrorist threat makes that stand even more necessary. "We want to be creative with the tools we have at our disposal," he said.

Tehran is negotiating on and off with Germany, France and Britain about suspending its enrichment operations in return for economic incentives.

The latest round ended Friday with no agreement, and an Iranian Foreign Ministry spokesman said Tuesday that "some nuclear activities" would resume at an undetermined date — apparently work on producing uranium hexafluoride, the gas feedstock for enrichment centrifuges.

Uranium enrichment itself "will remain the last option," said spokesman Hamid Reza Asefi.

U.S. President George W. Bush has proposed an outright ban on such dual-use nuclear technology, except in the United States and a dozen other countries that have it. Mohamed ElBaradei, head of the U.N. nuclear agency, instead proposes putting nuclear fuel production under multilateral control by regional or international bodies.

This approach has won some support at the U.N. conference, including from Russia's deputy foreign minister, who spoke Tuesday.

"There is no reason to create additional facilities for uranium enrichment," Sergei I. Kislyak said. "The world already has more than enough capacity."

Iran obtained its centrifuge equipment via a black market network based in Pakistan. Russia has supplied other nuclear components and is building a power reactor in southern Iran.

Moscow and Washington both support the European effort to resolve the Iran impasse. Kislyak said a solution is needed that "would meet the country's legitimate energy needs on the one hand and dispel doubts as to the peaceful nature of its nuclear activities on the other."

Under the 35-year-old nonproliferation treaty, states without nuclear arms pledge not to pursue them in exchange for a commitment by five nuclear powers — the United States, Russia, Britain, France and China — to move toward nuclear disarmament. Three other nuclear states — Israel, India and Pakistan — remain outside the treaty.

The treaty is reviewed every five years at conferences whose consensus positions give valuable political support to nonproliferation initiatives.