The US Congress continued to turn up the pressure on Iran Thursday, after Iranian President Mahmoud Ahmadinejad pledged not to retreat "even an iota" on its nuclear program.
Late Thursday, Iran was reported by Amercian and European officials to have rejected the idea of giving up custody, temporarily, of about three-quarters of its known quantities of low- enriched uranium - a central component of the effort to find a compromise on its nuclear program and prevent its development of nuclear weapons.
In Washington, a key Senate committee passed sanctions legislation meant to cripple Teheran's ability to import gasoline, a day after a House committee did the same.
The legislation still needs to pass a full session of both houses of the legislature before it can become law, but it showed that Congress was taking action even as Iran gave mixed messages on whether it would accept the Vienna proposal.
Ahmadinejad, in a speech to a rally on Thursday in the northeastern city of Mashhad, called enriching uranium Iran's "inalienable right" and said the West had moved from "confrontation to interaction."
Ahmadinejad said that "ground has been paved for nuclear cooperation" and Teheran was ready to work on nuclear fuel supplies and technical know-how with the UN nuclear watchdog, but then hedged on whether Iran would fulfill the agreement as it had been worked out.
He said Iran welcomed the international offer to ship out 70 percent of its enriched uranium to Russia for further enrichment, but was vague as to whether the Islamic Republic would sign the deal.
State Department spokesman Ian Kelly called the deal "a good agreement" that was "balanced," but didn't say whether the US was open to revising it.
Israel maintained a low profile Thursday on the issue, with no comment from the prime minister and restrained remarks from the defense minister.
This low-key response appeared to reflect a desire to avoid Israel "becoming the story," which is now focused on whether Teheran will accept the Vienna agreement.
Reuters reported Thursday that the nation had handed the International Atomic Energy Agency its response to the UN deal. The news agency cited state-owned Al-Alam TV. There was no information on the content or nature of the response, and no official confirmation from the IAEA.
Iran has been considering the deal for a week.
While Prime Minister Binyamin Netanyahu's office declined comment on the matter, Defense Minister Ehud Barak, during an interview with Israel Radio, reiterated his opposition to the plan, saying it would at most set the Iranian nuclear program back by just a year.
Another problem with the agreement, he said, is that it legitimizes Iran's enriching low-grade uranium for peaceful needs.
"That helps them in their argument that they are operating according to the non-proliferation treaty," he said, "and that is problematic for us."
Barak said Israel was telling its allies that while it was a positive move to try to get Iran to transfer its enriched uranium abroad for processing, it was still very important to demand an end to any enrichment in Iran.
Former Mossad head Danny Yatom told Israel Radio that a senior official in the US National Security Council had assured him that the US would not let up on the pressure to get the Iranians to stop uranium enrichment, even as they called on Teheran to transfer the enriched uranium in its hands abroad.
But, Yatom said, this demand did not get forceful articulation in the agreement now on the table.
He expressed concern that this agreement would lull the world to sleep and that the international community would be satisfied with any kind of agreement after so many years of discussion about the matter.
Ahmadinejad's speech suggested that Iran would stick by earlier comments that supported the framework of the deal, but demanded some changes. A key point was how quickly Iran was willing to send its stockpile of low-enriched uranium outside the country for further processing.
The Vienna-brokered plan requires Iran to send 1,100 kilograms of low-enriched uranium - around 70% of its stockpile - to Russia in one batch by the end of the year. After further enrichment there, France would convert the uranium into fuel rods and return them to Iran for use in a Teheran reactor that produces medical isotopes.
Western powers say it's critical for Iran to send out the 70% in one load to eliminate - at least temporarily - its options of making a nuclear weapon. A significantly lower amount or gradual shipments by Iran could jeopardize a key part of the proposal, which was reached after talks last week that included the United States. About 1,000 kilograms is the commonly accepted amount of low-enriched uranium needed to produce weapons-grade uranium for a single nuclear warhead.
Teheran signaled this week it wanted significant changes in the UN deal and to be allowed either to buy the fuel for the Teheran reactor from abroad or to ship the material in small batches.
That would not reduce fears about further enrichment to weapons-grade uranium, because Iran would be able to quickly replace small amounts it sent out of the country with newly enriched material.
Ahmadinejad said the West had pushed for halting Iran's nuclear program in the past, but that now it was "ready for cooperation and participation on exchange of nuclear fuel and building power plants."
The UN Security Council has slapped three sets of sanctions on Iran since the country refused to halt the uranium enrichment.
But the world now recognizes Iran's nuclear right, Ahmadinejad claimed.
"We welcome the West's change in behavior," he said, adding that Iran was ready to "shake any hand that is honestly extended toward us."
Also Thursday, a team of UN nuclear inspectors returned to the agency's headquarters in Vienna from a visit to the previously secret Iranian uranium enrichment site near Qom. It expressed satisfaction with the mission, but details have not been revealed.
What the inspectors saw - and how freely they were allowed to work - will be key in deciding whether the six world powers engaging Iran seek a new round of talks with Teheran.
Iran revealed it was building the Fordo enrichment site September 21 in a confidential letter to the IAEA. Just days later, the leaders of the US, Britain and France condemned Teheran for having kept it secret.
The West believes Iran revealed the site's existence only because it had learned that the US and its allies were about to make it public.