VIENNA -- The UN nuclear agency urged Iran yesterday to reinstate its suspension of nuclear fuel processing and ordered a comprehensive report on Tehran's adherence to key aspects of the Nuclear Nonproliferation Treaty.
The action, adopted unanimously by the International Atomic Energy Agency's 35-nation board of governors, was a victory for three European Union nations trying to persuade Iran to give up its efforts to master uranium enrichment technology.
Iran insists it needs enriched uranium to develop its own peaceful nuclear energy program. But several nations, including the United States, argue that Iran, as one of the world's leading oil producers, has little immediate need for nuclear energy and suspect Tehran wants to develop nuclear weapons.
The IAEA resolution, which expressed ''serious concern" over Tehran's decision to resume uranium conversion activities at a plant in Isfahan, also called on IAEA Director General Mohamed ElBaradei to present a major report to the board by Sept. 3 that would include findings of agency inspections conducted at all of Iran's known nuclear sites.
An agency diplomat, who spoke on condition of anonymity because of the issue's sensitivity, said the report could be used to build a case against Iran if the board decided to seek punitive measures from the UN Security Council. The United States has consistently advocated such action, although many countries are opposed to it.
''If they are going to build a case for the Security Council, it can't just be based on [Iran's] breaking a voluntary agreement" to suspend enrichment efforts, the diplomat said.
''It would have to be on a collection of sins. This would be the reference document."
The three European countries -- Britain, France, and Germany -- expressed hope that Iran would respond positively.
''We still believe there is a nonconfrontational way forward if Iran wants to take it," the British Foreign Office in London said in a written statement.
The United States, which decided to support the European diplomatic initiative earlier this year after originally maintaining its distance, also welcomed the result.
President Bush, speaking at his Crawford, Texas, ranch, described the IAEA action as a sign ''the world is coalescing around the notion that the Iranians should not have the means and the wherewithal to be able to develop a nuclear weapon."
In Washington, the State Department urged a tough approach.
''If Iran doesn't take the steps described in the resolution, we would expect that the next step would be referral to the Security Council," deputy spokesman Adam Ereli said at a State Department briefing.
Iran's IAEA ambassador, Sirus Nasseri, denounced the board's action as a denial of his country's right to peaceful nuclear energy as guaranteed under the 1968 Nuclear Nonproliferation Treaty.
''It signals the beginning of the road to an unwanted and undue confrontation through which . . . all parties stand to lose," Nasseri said.
He also accused the agency of applying a double standard that allows major powers including the United States to possess weapons-grade nuclear material while depriving developing nations access to even limited quantities.
''The point is, how can a small amount of feed material for enrichment to produce nuclear fuel [in Iran] be a matter of concern whereas a number of these states . . . are sitting on many tons of separated plutonium which can be directly diverted to nuclear weapons at any time of their choosing?" Nasseri said.
Despite his sharp tone, Nasseri also indicated that Iran was prepared to negotiate further.
Yesterday's action by the IAEA followed days of diplomatic maneuvering touched off by Tehran's announcement earlier this month that it would end its voluntary suspension of production at the Isfahan processing facility. Iran earlier this month also rejected as ''an insult" a long-awaited European offer of guaranteed nuclear fuel supplies plus a package of other economic incentives if Iran gave up its nuclear quest.