Chief Iranian nuclear negotiator Saeed Jalili, left, shakes hands with Kazakhstan's President Nursultan Nazarbayev prior their talks in Almaty, Kazakhstan, Monday, Feb. 25, 2013. Iran and six world powers, five permanent U.N. Security council members and Germany, are set to hold talks in Kazakhstan this week on Tehran's controversial nuclear program. (AP Photo/Pavel Mikheyev) EU foreign policy chief Catherine Ashton, left, and Kazakhstan's President Nursultan Nazarbayev greet each other prior their talks in Almaty, Kazakhstan, Monday, Feb. 25, 2013. ALMATY, Kazakhstan (AP) - World powers, fearful of scuttling negotiations beginning this week with Iran, are offering the Islamic republic some small new sanctions relief in return for curbing its nuclear program. But officials warned Monday that it's unlikely that any compromise will be reached soon. Negotiators set low expectations for the latest round of high-level diplomatic talks to begin Tuesday in Kazakhstan's largest city - the first since last June's meeting in Moscow that threatened to derail delicate efforts to convince Iran to stop enriching uranium to a level close to that used for nuclear warheads. The stakes couldn't be higher: the Obama administration is pushing for diplomacy to solve the impasse but has not ruled out the possibility of military intervention in Iran to prevent it from acquiring a nuclear weapon. And Israel has threatened it will use all means to stop Iran from being able to building a bomb, potentially as soon as this summer, raising the specter of a possible Mideast war. Tehran maintains it is enriching uranium only to make reactor fuel and medical isotopes, and insists it has a right to do so under international law. It has signaled it does not intend to stop, despite harsh international sanctions on its oil and financial sectors, and U.N. nuclear inspectors last week confirmed Iran has begun a major upgrade of its program at the country's main uranium enrichment site. The clerical regime's refusal frustrates the international community, which has responded by slapping Iran with a host of economic sanctions that U.S. officials said have, among other things, cut the nation's daily oil output by 1 million barrels and slashed its employment rate. But, in a twist, negotiators now hope that easing some of the sanctions will make Tehran more agreeable to halting production of 20 percent enriched uranium - the highest grade of enrichment that Iran has acknowledged and one that experts say could be turned into warhead grade in a matter of months. Negotiators from the six world powers - United States, Russia, China, Britain, France and Germany - also want Iran to suspend enrichment in its underground Fordo nuclear facility, and to ship its stockpile of high-grade uranium out of the country. We are pleased that they have come together for talks because it's been eight months since Moscow. We wanted to come together for talks earlier than this," said Michael Mann, spokesman for EU foreign policy chief Catherine Ashton, who is leading the negotiations. What's important to us is that they engage in these negotiations and take seriously what we've put on the table. "No one is expecting everyone to walk out of here with a deal, but if we can have some forward momentum and they can show a willingness to take a confidence-building step, that's very important," Mann told reporters on Monday. He described the world powers' newest gambit as "a good offer" but declined to say what it would include. A senior U.S. official at the talks said some sanctions relief would be part of the offer to Iran but also refused to detail it. The new relief is part of a package that the U.S. official said included "substantive changes - whether you'd call them super-substantial, I'll leave to history." The official acknowledged reports earlier this month that sanctions would be eased to allow Iran's gold trade to progress, but would neither confirm nor deny they are included in the new relief offer, and spoke only on condition of anonymity to discuss the sensitive diplomatic talks more candidly. But at the same time, the senior U.S. official also noted the possibility that Iran would face new pressures if it fails to comply with international concerns. That could include toughening the impact of the sanctions already in place by enforcing them more strictly, or imposing new sanctions altogether as Iran moves forward with its program. Western powers have hoped that the Iranian public would suffer under sanctions so badly that the government would feel a moral obligation to slow its nuclear program. The U.S. official attributed the decline in Iranian currency, the rial, and the decrease in oil production to Western sanctions. Iran has been unimpressed with earlier offers by the powers to provide it with medical isotopes and lift sanctions on spare parts for civilian airliners, and new bargaining chips that Tehran sees as minor are likely to be snubbed as well. Iran insists, as a starting point, that world powers must recognize the republic's right to enrich uranium. In a sign that Tehran is in no hurry to reach a compromise, Iran's foreign minister has no plans to meet with officials of the International Atomic Energy Agency Tuesday when he visits Vienna to attend an unrelated conference. Diplomats in Vienna suggested the decision by Foreign Minister Ali Akbar Salehi reflects a deadlock on the agency's attempts to probe Tehran's atomic work. IAEA officials recently suggested related talks needed to pause after dragging on without results. The diplomats demanded anonymity because their information was confidential. Still, last week, Salehi spokesman Ramin Mehmanparast said the Almaty talks could provide an important "opportunity" so long as the two sides were dealing with each other as equals and making offers of "same level, same weight." "We will offer ways for removing possible concerns and ambiguities to show our goodwill, if Western countries, especially the U.S., fully recognize the nuclear rights of countries, which shows their goodwill," Mehmanparast told reporters in Tehran. In London, Secretary of State John Kerry said an Iran with nuclear weapons was "simply unacceptable" and warned the time limit for a diplomatic solution was running out. "As we have repeatedly made clear, the window for a diplomatic solution simply cannot remain open forever," said Kerry, on his first international tour as America's top diplomat. But it is open today. It is open now and there is still time but there is only time if Iran makes the decision to come to the table and to negotiate in good faith. We are prepared to negotiate in good faith, in mutual respect, in an effort to avoid whatever terrible consequences could follow failure and so the choice really is in the hands of the Iranians. And we hope they will make the right choice. An analysis released Monday by the International Crisis Group concluded that the web of international sanctions have become so entrenched in Iran's political and economic systems that they cannot be easily lifted piece-by-piece. It found that Tehran's clerical regime has begun adapting its policy to the sanctions, despite their crippling effect on the Iranian public. Doing so, the analysis concluded, has divided the public's anger "between a regime viewed as incompetent and an outside world seen as uncaring." As far as Iran is concerned, it is too late to reverse course. The massive sanctions regime is in place, warts and all, and not about to be removed," the analysis concluded. It recommended that the world powers "devise a package of incentives, including some less than complete degree of relief, that is politically as well as legally achievable and that genuinely addresses Iranian concerns." Several diplomats in Almaty said any major breakthrough in the negotiations likely won't come until after Iran's presidential elections in June - especially if the world powers refuse to offer anything that Tehran can use to show as some kind of major concession by the West. Associated Press Writers Peter Leonard, George Jahn in Vienna and Cassandra Vinograd in London contributed to this report. Follow Lara Jakes on Twitter at http://twitter.com/larajakesAP