VIENNA -- The UN nuclear agency agreed yesterday on a plan for policing Iran's nuclear programs designed to avoid a showdown at the United Nations.
But Iran's representative immediately raised questions about the wording of the pact, and the United States said it retained the right to take the case to the UN Security Council on its own.
US chief delegate Jackie Sanders listed more than a dozen open questions about Iran's past nuclear activities still before the International Atomic Energy Agency, despite a nearly two-year investigation.
"This makes it clear that the IAEA cannot . . . offer the necessary assurances that Iran is not attempting to produce nuclear material for weapons," she told the agency's board of directors.
Sanders spoke shortly after the board passed a toned-down resolution authorizing IAEA head Mohamed ElBaradei to monitor Iran's commitment to freeze uranium enrichment activities that can produce either low-grade nuclear fuel or the raw material for atomic weapons.
The issue of what is included in the suspension of activities had dominated the meeting since it opened Thursday, with the Iranian insistence on exempting some equipment forcing the meeting to continue yesterday, after a weekend adjournment.
The United States -- which had labeled Iran part of an "axis of evil" with North Korea and prewar Iraq -- wants Iran referred to the Security Council, where it could face sanctions for allegedly violating the Nuclear Nonproliferation Treaty.
"We believe Iran's nuclear weapons program poses a growing threat to international peace and security," Sanders said, alluding to the possibility of a unilateral US push. "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."
White House press secretary Scott McClellan urged vigilance, telling reporters in Washington "the implementation and verification of the agreement is critical."
France, Germany, and Britain, who negotiated an agreement Nov. 7 with Iran on the suspension, said the deal meant that all equipment used for enrichment must be at a standstill.
Iran, which insists its nuclear program is peaceful, had demanded it be allowed to run 20 centrifuges for research.
Seeking to avoid tough measures by the board that could have led to referral to the Security Council, Iran delivered a letter to the agency Sunday pledging "not to conduct any testing with these sets of components."
Hossein Mousavian, the chief Iranian delegate to the meeting, said the commitment meant "we are not going to introduce material or any gas" into the centrifuges -- a pledge that appeared to fall short of the European demands.
Later, Iranian delegate Cyrus Nasseri appeared to move closer to the European interpretation, telling reporters Iran "will not" run even empty centrifuges.
The enrichment process involves introducing uranium hexafluoride gas into centrifuges that then spin them to low-level nuclear fuel or highly enriched uranium used in the core of nuclear warheads.
Delegates to the meeting, including senior diplomats with nuclear expertise, suggested the contradictory language was meant to ease fears among Iranian hard-liners that Tehran gave up too much in exchange for a resolution that did not include an indirect mention of possible Security Council referral.