The U.N. nuclear watchdog agency passed a toned-down resolution Monday on policing Iran's commitment to freeze all programs linked to uranium enrichment in an effort to defuse a dispute that had threatened to go to the Security Council (search).

However, confusion over what the freeze encompassed appeared to give Iran loopholes in interpreting its commitments. The vote by the International Atomic Energy Agency (search ) board came after a senior Iranian official seemed to cast doubt on his country's latest commitment to a total suspension of nuclear activities capable of producing weapons-grade uranium.

The United States, which maintains Iran (search) is trying to make nuclear arms, accused Tehran of representing a "growing threat to peace and security" and said that if it failed to find international consensus to have Iran referred to the U.N. Security Council, it could do it itself.

At issue is whether Iran has promised not to operate any of its centrifuges that spin gas into uranium for fuel or for use in nuclear weapons. European nations say Iran agreed not to operate any centrifuges at all, but Iran has said it wanted to use 20 centrifuges for research purposes.

Diplomats from the European Union and elsewhere said the Iranian commitment — sent by letter to the IAEA in Vienna on Sunday — fulfilled demands that Tehran include centrifuges in its total suspension of uranium-enrichment programs.

The letter commits Tehran "not to conduct any testing with these sets of components," IAEA spokesman Mark Gwozdecky said Monday, quoting excerpts.

Hossein Mousavian, the chief Iranian delegate to the meeting, told reporters: "We (only) said there would no testing."

"Definitely we are not going to introduce material or any gas" into the centrifuges, he added, declining to answer whether Iran's understanding of a freeze matched that of international demands that the devices be left at a complete standstill.

France, Germany and Britain, who negotiated a Nov. 7 agreement with Iran on suspension, went into the IAEA board meeting last week saying full suspension meant that all equipment used for uranium enrichment must not be used. That full suspension would be in effect while the two sides discuss a pact meant to provide Iran with EU technical and economic aid and other concessions. Those talks are set for mid-December.

Delegates and other diplomats with nuclear expertise agreed Mousavian's remarks did not meet the European definition of suspension.

But they suggested the comments were meant to ease fears among Iranian hard-liners that Tehran gave up too much in exchange for a softly worded resolution on policing its commitment. They said they still believed Iran would not run any centrifuges during the suspension.

In Tehran, government spokesman Abdollah Ramezanzadeh said Iran had agreed not to test any centrifuges "for now."

In return, France, Germany and Britain accepted Iran's demand to further water down a draft resolution on policing the suspension — a text adopted Monday afternoon by the IAEA board. It included an extra phrase insisted on by the Iranians emphasizing that suspension is not a legal or binding obligation on Tehran's part.

The United States — which has labeled Iran part of an "axis of evil" with North Korea and prewar Iraq and wants it referred to the Security Council for allegedly violating the Nuclear Nonproliferation Treaty — was unhappy with the resolution.

Listing a series of open questions about Iran's past nuclear activities, which only became public about two years ago, chief U.S. delegate Jackie Sanders told the meeting Tehran could not be trusted.

"We believe Iran's nuclear weapons program poses a growing threat to international peace and security," she said.

"Any member of the United Nations may bring to the attention of the Security Council any situation that might endanger the maintenance of international peace and security," she said, alluding to the possibility of a unilateral U.S. push to refer Iran to the Council.

Under the European agreement, the 20 centrifuges Iran had previously wanted exempted would not be placed under IAEA seals but monitored by cameras.

IAEA head Mohamed ElBaradei evaded questions on whether the commitment not to test was enough, telling reporters only that the centrifuges were not operating presently and "we clearly would report to the board should there be any change of status."

The proposed deal also commits Iran to a pledge not to reprocess plutonium — which it would be able to do in several years' time, once it completes work on a heavy water reactor in the city of Arak.

With the EU deal envisaging a light-water reactor for Iran — from which extraction of weapons-grade nuclear material is difficult — diplomats said the Europeans hoped Iran would not complete its heavy-water facility.