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Iran vowed Thursday to resist any deadline to prove its nuclear programs are peaceful, even as support for such a measure grew among leading members of the U.N. atomic agency.

The board of governors' meeting of the International Atomic Energy Agency (search) adjourned for a second day to allow member nations to discuss informally how to learn the full extent of Iran's nuclear activities.

A U.S-supported draft resolution would essentially require Iran by next month to disprove suspicions it is running a covert nuclear weapons program, and the measure's backers said about 20 of the board's 35 nations indicated they would vote for it.

Tehran warns that such a demand could aggravate nuclear tensions and says it will fight any deadline attempt, an implicit warning that it might break off all ties with the agency.

"We will oppose that," chief Iranian delegate Ali Akbar Salehi (search) told The Associated Press. "Nobody is in a position to impose a deadline on a sovereign country."

But the head of the IAEA said Wednesday the agency's board still favored the October deadline.

"I think there is broad agreement that the board would like to see a deadline," IAEA Director General Mohamed ElBaradei (search) said, adding he personally wanted "an immediate disclosure of all nuclear activities" by Iran.

Underlying the need for quick action, ElBaradei also said that unless Iran cooperated, he and his agency might soon be unable to verify whether Tehran was diverting nuclear material into a weapons program. Those fears, expressed at a closed session of the board meeting, were relayed by diplomats present.

The draft resolution, while not outlining consequences, indirectly threatened U.N. Security Council involvement if the board rules at its November meeting that Iran ignored IAEA demands.

The United States accuses Iran of working on a secret atomic weapons program and says Tehran has violated provisions of the treaty banning the spread of nuclear weapons. Chief U.S. delegate Kenneth Brill called Iran to task based on a report outlining discrepancies between Tehran's past statements on its nuclear program and IAEA findings.

The report, by ElBaradei, lists the discovery of weapons-grade enriched uranium and other evidence that critics say point to a weapons program.

Tehran insists its programs are for generating electricity and says its equipment was "contaminated" with enriched uranium by a previous owner.

The United States had pushed for a resolution finding Iran in noncompliance of a part of the treaty banning the spread of nuclear arms. That could have brought the matter before the Security Council, which in turn could have called for sanctions. But a lack of support at the board meeting scuttled that plan.

The U.S.-backed draft resolution submitted by France, Germany and Britain to the closed meeting called on Iran to "provide accelerated cooperation" with agency efforts to clear up the questions.

It also urged Iran to "ensure there are no further failures" in reporting obligations and called on it to "suspend all further uranium enrichment-related activities, including the further introduction of nuclear material" into a facility where IAEA inspectors found traces of weapons-grade enriched uranium.

Besides expressing concern about the weapons-grade uranium, the IAEA report to the board also questioned the purpose of tests and programs that experts say make little sense unless the country was pursuing nuclear weapons.