Tehran has warned of "unpredictable consequences" if the UN watchdog finds it in breach of a global pact against atomic weapons, as Washington accuses the United Nations of playing down "evidence" Iran wants a bomb.
On November 20, the International Atomic Energy Agency's (IAEA) Board of Governors meets to discuss an IAEA report on Iran's nuclear programme, detailing decades of failures by Iran to report truthfully about its activities and facilities.
The United States wants the board to declare Iran in violation of its obligations under the nuclear Non-Proliferation Treaty (NPT), which would require it to report Iran to the UN Security Council for possible economic sanctions.
"I hope we do not reach such a stage because then things could very easily get out of control," Iran's ambassador to the IAEA, Ali Akbar Salehi, told Reuters in an interview today.
"And then it could lead to unpredictable consequences. We don't even want to think about such a situation," he added, without elaborating.
The IAEA's report concluded there was "no evidence" to date that Iran's nuclear programme was for anything but peaceful purposes, but said the jury was still out.
In the first US reaction, Undersecretary of State John Bolton said on Wednesday this was "impossible to believe" and that the report reaffirmed the U.S. view that Iran's concealment would "make sense only as part of a nuclear weapons programme".
But the IAEA stuck to its guns. "We stand by the report, but it's classified and will be considered at next week's (IAEA) board meeting," spokesman Mark Gwozdecky said. He declined to comment further.
The IAEA report said Iran hid a centrifuge uranium enrichment programme for 18 years and produced small amounts of plutonium, useable in a bomb and with scant civilian uses.
Although diplomats said Washington had few allies on the IAEA board, they said it was searching for a compromise with France, Britain and Germany, who would prefer to encourage Iran to keep cooperating with the United Nations than punish past failures.
Such a compromise might include a word synonymous with violation in the text of a resolution, couched in compliments of Iran's new style of full cooperation with the United Nations.
But Salehi said this would be "unacceptable" to Iran.
Referring to a deal struck by the foreign ministers of France, Germany and Britain on October 21 in Tehran, Salehi said the three countries should keep their word and not support any US-backed IAEA board resolution stating that Iran was in any way in non-compliance.
"We are testing how far we can trust the words of the Europeans on this particular issue. We have taken action on our words. We hope that the Europeans also take action on their words," Salehi said.
Iran had agreed with the Europeans to suspend its controversial uranium enrichment programme and sign the NPT Additional Protocol permitting the IAEA to perform more intrusive, short-notice inspections of all its nuclear sites.