Iran agreed Tuesday to suspend uranium enrichment (search) and give inspectors unrestricted access to its nuclear facilities as demanded by the U.N. watchdog agency, a step that could ease the standoff over fears Iran is seeking to build nuclear weapons.

The announcement came after weeks of pressure on Iran to meet an Oct. 31 deadline to come clean on its nuclear program, which Washington believes aims to build a nuclear arsenal. The United States -- which has led the charge for the U.N. Security Council (search) to take action against Tehran -- gave a cautious welcome.

If Iran follows through with its promises, it "would be a positive step in the right direction," White House press secretary Scott McClellan said. "Full compliance by Iran will now be essential."

Iran, which says its nuclear programs aims only for electricity production, made the commitments after the foreign ministers of Britain, France and Germany came to Iran to press the demands by the U.N. International Atomic Energy Agency (search). Tehran did not say when it would take the steps, though a British official said it would likely be before the deadline.

Iran also agreed to hand over other information long sought by the IAEA, said diplomats in Vienna, where the IAEA is based. Most importantly, said the diplomats, who spoke on condition of anonymity, Iran promised to account for the origin of traces of weapons-grade uranium IAEA inspectors discovered at two facilities, raising alarm bells in Vienna and Washington.

IAEA head Mohamed ElBaradei has called those traces, found in environmental samples, the most troubling aspect of Iran's nuclear activities. Iran says the contamination was on equipment it imported for peaceful nuclear purposes, but it resisted IAEA requests that it name the country of origin. Once the agency knows where the equipment comes from, it can test the truth of Iran's claims.

The direct intervention by the three European ministers -- who flew to Tehran for talks Tuesday, after which Iranian officials announced their promises -- highlighted the differing strategies Europe and Washington have toward Iran's Islamic government.

The United States characterized Iran as part of an "axis of evil" -- alongside Iraq, whose regime U.S. troops later ousted. Washington has pushed fellow members of the IAEA board to declare Tehran in breach of the Nuclear Nonproliferation Treaty. That would likely prompt the U.N. Security Council to impose sanctions on Iran.

The head of Israel's military intelligence warned on Tuesday that if Iran completes its program for enriching uranium, it would be able to produce its own nuclear weapons without outside help by the summer of 2004.

The Europeans have tried to engage the Tehran government. On Tuesday, the three ministers promised that if Iran does meet its commitments, their countries will help it get peaceful nuclear technology.

The intervention to help resolve the nuclear dispute with Iran also gave the three European powers the chance to show unity after the divisions of the Iraq war, in which France and Germany opposed military action, while Britain sided with Washington.

"The Europeans are united on Iran," said Volker Perthes, a German foreign policy analyst. "Naturally, they are eager to demonstrate that unity."

Europe, he said, wanted to show it "can wield influence in a different way than the Americans did in Iraq. ... It was a signal: We also don't want Iran to develop their nuclear program ... but we have something else on offer -- cooperation, stronger economic integration."

In New York, U.N. Secretary-General Kofi Annan said he appreciated the efforts of Iran and the foreign ministers and urged Iran to "further cooperate" with the IAEA to resolve all outstanding issues, U.N. deputy spokeswoman Hua Jiang said.

German Foreign Minister Joschka Fischer urged Iran to carry out its promises. "We reached an agreement which must now be implemented. This is crucial," he told reporters after returning home from Tehran. "It offers a great opportunity for Iran that shouldn't be missed."

Fischer, Jack Straw of Britain and Dominique de Villepin of France said in a joint statement with Iran after their talks that if the IAEA affirms that Iran has implemented its decisions, that "should enable the immediate situation to be resolved by the IAEA board."

Iran has been keen to avoid the Security Council sanctions and has let IAEA inspectors view some sites, including at least one military facility. But for weeks it hesitated at making a full commitment to the IAEA demands.

After Tuesday's talks, a senior Iranian official announced that Iran would sign an additional protocol to the Nuclear Nonproliferation Treaty allowing inspectors to enter any site they deem fit without notice.

"The protocol should not threaten our national security, national interests and national pride," said Hasan Rowhani, the secretary of Iran's powerful Supreme National Security Council. In the joint statement, Iran said it would abide by the protocol even before it is ratified by parliament, as is required.

Rowhani said that for an "interim period," Iran will suspend nuclear enrichment -- though he did not say for how long -- to "create a new atmosphere of trust and confidence."

The three foreign ministers also said that if Iran proves its nuclear program is only for energy production, they would make it easier for it to get nuclear technology. Iran has accused the United States of using its influence to block such purchases.

During Tuesday's talks in an Iranian government palace, about 150 Iranian students opposed to giving ground on the nuclear issue demonstrated outside.

"Iran would rather die than compromise," read one banner hoisted by the student protesters.