VIENNA (Reuters) -- The United States is willing to give Iran time to decide whether to accept a UN draft deal that is meant to defuse nuclear tensions with world powers but has drawn Iranian objections, a U.S. diplomat has said.
The proposal for Iran to part with stocks of potential nuclear explosive material in exchange for fuel to keep a nuclear medicine facility running has stumbled on Iranian calls for amendments, but Iran has not rejected it outright.
Addressing Iran's misgivings over sending low-enriched uranium (LEU) abroad before it receives reactor fuel in return, the UN nuclear agency chief has suggested Iran place the LEU in a friendly third country pending arrival of the fuel.
A senior Iranian official rejected the idea at the weekend.
But Tehran has yet to give a full, official reply on the proposal drafted by International Atomic Energy Agency chief Muhammad el-Baradei three weeks ago after consultations with Iran, France, Russia, and the United States.
"There have been communications back and forth. We are in extra innings in these negotiations. That's sometimes the way these things go," said Glyn Davies, U.S. ambassador to the IAEA.
"We want to give some space to Iran to work through this. It's a tough issue for them, quite obviously, and we're hoping for an early positive answer from the Iranians."
Iran next year will run out of specially fabricated fuel imported in 1993 to run a Tehran research reactor that produces radioactive isotopes for cancer treatment.
World powers saw a "win-win" deal when they thought of providing the fuel needed in return for Iran cutting its LEU stockpile below the threshold at which it could be further refined into fissile material for a nuclear warhead.
In talks with six powers in Geneva on October 1, Iran agreed in principle to send the bulk of its LEU to Russia and France for further processing and conversion into fuel plates for the Tehran reactor, Western officials said.
But they said Iran balked at fleshing out details in Vienna and seemed to retreat from the point of the deal hatched in Geneva -- to ease suspicions of a bomb agenda in Iran raised by its record of nuclear secrecy and curbs on IAEA inspections.
El-Baradei's plan would have Iran send out 75 percent of its LEU stocks by the end of this year and get it back as fuel for the Tehran research reactor.
Iranian officials have variously said Tehran should give up no LEU because it is a vital strategic asset against enemies like the United States and Israel, or it could send some out but only in simultaneous exchange for reactor fuel.
They have left unclear what Iran's red line will be, but the changes mooted so far are nonstarters for the West as they would mean no reduction of the LEU reserve, now enough for use in one to two nuclear bombs if enriched to high purity.
U.S. Secretary of State Hillary Clinton said last week the deal would not be reworked and urged Iran to accept it to inspire trust in its professed intention to use enriched uranium only for peaceful energy or medicine.
"Iran has the opportunity to embrace this deal, and it's a very good, very positive...and fair deal. It would do much to move this process forward," Davies said in Vienna.
"When the reactor's fuel run out next year, we would help to keep it going. There are hospitals, doctors, cancer patients who rely on the material produced there. We know the leadership in Tehran needs to keep the reactor going. We would like to help with that effort," he said.