Vice Premier Silvan Shalom called last week's offer to Iran a "bad mistake" that the world will pay for in the near future, the harshest statement yet to come out of Jerusalem about the deal that would have Iran send a batch of uranium to Russia and then to France for processing.
"Iran will not change its path," Shalom said in a meeting at the UN on Friday with Secretary-General Ban Ki-moon. "Iran's intentions go beyond its nuclear program. Iran wants to bring back the Persian Empire, and in its view this type of agreement is a way of buying time."
Shalom said Teheran was laughing at and "deceiving the entire world," taking advantage of "naÃ¯vetÃ© and turning the agreement into a powder keg that will explode in our faces."
According to a statement put out by his office, Shalom told Ban that Iran would never give up its nuclear ambitions, and that its aim was simply to "gain time."
"The agreement that was signed is a bad mistake that we are likely to pay for in the not-too-distant future," he said.
Shalom's comments went beyond those of any other government minister so far on Iran.
President Shimon Peres, in an interview with Newsweek, said he was "a little bit worried" about the agreement, "because the policy should be of prevention, not just of inspection - to prevent the building of a bomb."
Asked whether he thought the Iranians were merely stalling for time, Peres said his impression was that they were trying "to maneuver rather than to agree. To create an impression of an agreement without agreeing. But, you know, I don't think our people or the Americans are foolish."
The comments coming from Israel came as Iran put off until this week a formal response to the UN-backed plan to ship much of its uranium to Russia for enrichment, the country's nuclear envoy said on Friday.
Ali Asghar Soltanieh, Iran's representative to the International Atomic Energy Agency, said Teheran was still studying the proposal and would inform the UN nuclear watchdog "next week about our evaluation."
"We are working and elaborating on all the details of this proposal," Soltanieh told state Press TV.
The plan was put forth on Wednesday after three days of talks between Iran and world powers in Vienna. The United States, Russia and France endorsed the deal on Friday, when an official response from Teheran had been expected.
The State Department expressed mild disappointment that Iran withheld a decision and said it was unhappy Iran was not ready to embrace the proposal.
The plan is attractive to the US because it would consume a large amount of Iran's stockpile of low-enriched uranium, thereby limiting the potential for Teheran to secretly convert it into uranium suitable for a nuclear bomb.
Defense Minister Ehud Barak, however, said on Thursday that at most the plan would delay Iran's nuclear program by a year.
State Department spokesman Ian C. Kelly said the US still hopes Teheran will go along with the IAEA option.
"This is a real opportunity for Iran to help address some of the real concerns of the international community about its nuclear program and at the same time still provide for the humanitarian needs of the Iranian people," Kelly said. "We hope that they will next week provide a positive response."
Soltanieh's statement came on the eve of a visit by UN nuclear experts to Iran to inspect the recently disclosed uranium enrichment facility near Qom. The visit kicked off late on Saturday.
The IAEA said on Friday that Iran told agency chief Mohamed ElBaradei it is "considering the [UN] proposal in depth and in a favorable light, but needs time until the middle of next week to provide a response."
Hours earlier, Iranian state TV quoted an unidentified official close to the Iranian nuclear negotiating team as saying that Teheran wants to buy nuclear fuel it needs for a research reactor, rather than accept the UN plan.
The TV quoted the official as saying Iran was waiting for a response from world powers to its own proposal to buy the 20 percent-enriched uranium it needs for its Teheran reactor that produces medical isotopes. The US-built reactor has been producing medical isotopes for more than three decades.
While the TV report was not an outright rejection of the UN proposal, it raised concerns since Iran has often used counterproposals to draw out nuclear talks with the West.
On Thursday, deputy speaker of the parliament Muhammad Reza Bahonar dismissed the UN plan.
David Albright, a former UN nuclear inspector now with the Institute for Science and International Security in Washington, said the Iranian proposal to buy nuclear fuel is a nonstarter because UN sanctions stand in the way of anyone willing to sell Teheran enriched uranium.
"The IAEA plan was pretty clear, it was goodwill test by the Obama administration to see if Iran is serious about being prepared to negotiate," Albright said. "Iran would put itself in a bad position if it rejects a very reasonable offer made in good faith."
The Vienna talks followed a similar meeting on October 1 in Geneva that included the highest-level bilateral contact between the US and Iran in years. At the time, the revelation that Iran has been building a nuclear plant for uranium enrichment near Qom had heightened international concerns.
Iran is enriching uranium to a 3.5% level for a nuclear power plant it is planning to build in southwestern Iran. Iranian officials have said it is more economical to purchase the more highly enriched uranium needed for the Teheran reactor than to produce it domestically.
The Vienna-brokered plan would require 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 in Russia, France would have converted the uranium into fuel rods for return to Iran for use in the Teheran reactor.
Some 1,000 kilograms is the commonly accepted amount of low-enriched uranium needed to produce weapons-grade uranium for a single nuclear warhead.
Meanwhile on Saturday, Iranian parliament speaker Ali Larijani called the UN-drafted an attempt by the West to "cheat" the Islamic Republic, AFP reported.
"Westerners are insisting to go in a direction that speaks of cheating and are imposing some things on us," Larijani reportedly told the Iranian IRNA news agency.
"They are saying we will give you the 20% [enriched uranium] fuel for the Teheran reactor only if you give us your enriched uranium. I see no link between these two things," he reportedly said.