Most participants at a key 35-nation meeting of the U.N. nuclear watchdog agency have agreed to deny Iran technical aid for its plutonium-producing reactor, diplomats at the gathering said Tuesday.

The diplomats — all participating in an International Atomic Energy Agency committee meeting — said the tentative agreement foresaw approving Tehran's requests for IAEA aid on seven other nuclear projects but refusing its call for help in building the Arak reactor.

The decision would be formally made on Thursday, once the committee looking at hundreds of requests for IAEA technical aid from member countries ends its work and the full board meeting begins. The chairman of that meeting would announce approval of all the projects except for Arak, said four diplomats, speaking independently and asking for anonymity because they were not authorized to discuss the closed board meeting.

The decision to deny the aid — either directly or indirectly, by deferring a ruling — was expected to be adopted by consensus, they told The Associated Press. But even if one of Iran's allies on the board — most likely Cuba — forced a vote, those opposed to the Arak project would prevail, they said.

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The diplomats emphasized that agreement was tentative. But all agreed this was the most likely scenario to resolve differences pitting not only nonaligned nations — traditional Iran allies — against the United States and its backers but also leading to tensions within the Western camp.

In comments to the closed committee made available to The Associated Press before delivery, Iran's chief delegate Ali Ashgar Soltanieh lambasted nations opposing aid for Arak, accusing them of "imposing their politically motivated and discriminatory policies" on the meeting.

Alluding to the United States and its allies, Soltanieh accused them of ignoring the dangers that Israel — widely considered to be a country with nuclear weapons — posed to the Middle East.

"Sooner or later the governments of these countries will be brought to judgment and shall be questioned for deception of their own nation as well as (the) international community," he declared.

The agency routinely approves hundreds of technical aid projects each year, most of them dealing with nuclear medicine, agricultural pest prevention and similar programs that have no obvious link to atomic arms. Iran says the reactor will produce nuclear isotopes for medical use.

But fears that Tehran might be seeking to develop an arms program — either through uranium enrichment or plutonium reprocessing — turned this year's technical aid committee meeting into a heavily politicized event.

Even nonaligned nations traditionally supportive of Iran were likely to approve some form of denying help for Arak. The other seven projects were less controversial.

One asks for help in developing nuclear capabilities for medical use. Another seeks legal aid for the Russian-built Bushehr reactor, which even the Americans have accepted as not posing a threat of nuclear proliferation. The five others ask for assistance in administrative or safety aspects of nuclear power, according to a list made available to the AP.

Denying Iran help with Arak — where it is seeking agency assistance to make sure the reactor is environmentally safe — would do little to slow construction of that facility or affect Tehran's other potential avenue to weapons production — uranium enrichment. Still, it would maintain at least symbolic pressure, even with a Security Council deadlock over how to sanction Tehran for its nuclear defiance.

Signs of compromise emerged on Monday — the first day of the gathering — when the United States said it would accept Tehran's requests for U.N. aid on seven of eight nuclear projects but not its request for help on Arak.

The decision reflected the U.S. stance coming into the meeting that it was useless to try to block IAEA help to Iran on all eight projects because of opposition by most of the board. This opposition was later strengthened by an IAEA ruling that the aid being contemplated for all the projects did not pose a proliferation threat.

Some diplomats accredited to the Vienna-based U.N. nuclear watchdog agency suggested it could reflect a U.S. decision to tread relatively lightly while Washington weighs the pros and cons of seeking direct dialogue with Tehran on reducing Iraq violence. U.S. officials declined comment.

Chief U.S. delegate Gregory L. Schulte described Arak as being "capable of producing plutonium for one or more nuclear weapons each year" once completed, likely in the next decade.

"Given past board decisions, continued questions about Iran's nuclear program, and the risk of plutonium being diverted to use in a weapons, the United States joins with others who cannot approve this project," he said.

The European Union also urged the board not to approve aid for Arak.

The U.N. Security Council's main concern is Tehran's uranium enrichment program — and Iran's defiance of its demand in July that it freeze enrichment. But the Arak heavy water reactor's future ability to produce plutonium also is worrying.

A council resolution did not specifically mention Arak, saying only that Tehran had to stop all "reprocessing activities."