Iran threatened on Wednesday to resume uranium enrichment, a process that could be used to make atomic bombs, if the UN nuclear agency passed a toughly-worded resolution rebuking Tehran for poor co-operation.
The United States immediately accused Iran of trying to bully the board of the International Atomic Energy Agency (IAEA), meeting in Vienna, and said such tactics increased suspicions that Tehran was secretly making weapons.
"The basic message that Iran is sending is that they have something to hide and they're going to use any means they have, including intimidation, to keep things from coming to light," US ambassador to the UN in Vienna Kenneth Brill said.
In his toughest warning to the IAEA yet, Iranian President Mohammad Khatami described as "very bad" a resolution drafted by Britain, Germany and France that "deplores" Iran's inadequate co-operation with the agency.
"I am not saying we will do something particular, but if this resolution passes, Iran will have no moral commitment to suspend uranium enrichment," he told reporters.
Iran, which denies it is seeking weapons, says it wants to produce low-grade enriched uranium as fuel for nuclear power reactors. But Washington and many European states fear it could use the technology to make highly-enriched, bomb-grade uranium.
Khatami, aware that Washington wants its case sent to the UN Security Council for possible sanctions, balanced his tough line with assurances that Iran's nuclear aims were peaceful and that Tehran did not plan to kick out UN inspectors.
"We have no intention of using nuclear technology for military use," he said. "We will continue our co-operation with the agency in the framework of the law and our rights."
In Vienna, several diplomats said a majority of the IAEA board backed the draft resolution and it was unlikely the text would be greatly changed.
The draft was expected to go before the board for formal debate later on Wednesday, and the board could take a formal position as early as Thursday, they said.
Hossein Mousavian, head of Iran's delegation in Vienna, said Iran might end its partnership with Britain, Germany and France, who brokered an agreement last year that led to Iran suspending uranium enrichment and agreeing to snap nuclear inspections.
To the Europeans' annoyance, Iran has never completely stopped enrichment-related activities.
"Despite the threats from Iran, the Europeans are standing firm. This is typical brinkmanship on the part of Iran," a Western diplomat from an influential IAEA board member said.
Joe Cirincione, a nuclear expert at the Carnegie Endowment for International Peace think-tank in Washington, said most IAEA board members believed Iran was playing a "cat and mouse" game with the IAEA while pursuing secret weapons-related activities.
"This is why the EU strategy is to suspend the enrichment programme. You stop that while the IAEA is carrying out inspections," he said.
Iran says the resolution under discussion in Vienna has blown technical shortcomings out of proportion and is driven by an anti-Iranian political agenda in the United States.