Iran's chief nuclear negotiator Saeed Jalili stipulated Thursday that any breakthrough in the upcoming round of talks with the so-called P5+1 group would only be possible if the powers recognize the Islamic Republic's right to enrich uranium independently.

"We think our talks tomorrow can go forward with one word. That is the acceptance of the rights of Iran, particularly the right to enrichment," he said in a speech at Almaty University, referring to the negotiations with the five permanent members of the United Nations Security Council – the United States, Russia, China, the United Kingdom and France – plus Germany, which are set to begin on Friday in Almaty, Kazakhstan.

On the eve of negotiations, senior American officials said that the focus of the discussions would be Iran’s response to the offer made previously by the six powers, suggesting that Iran restrict its enrichment of uranium to what is considered a high level of 20 percent and suspend its operations at the underground facility at Fordow, in exchange for an easing of sanctions.

The current round of talks will be an extension of the previous round, held in Kazakhstan at the end of February. In the course of those discussions, representatives of the six powers presented the Iranians with a new, more moderate proposal. Two weeks ago, low-level talks were held in Istanbul with Iranian officials. During a 12-hour meeting, the Iranians received numerous responses and clarifications regarding the new proposals.

A senior American official who is part of the negotiating team said that the powers expect Iran to come up with a clear and significant reply to the offer during the present round of talks. He added that the offer is balanced and fair and addresses the most urgent issue causing concern to the international community, namely the enrichment of uranium to the 20 percent mark.

In his speech at the United Nations in September 2012, Prime Minister Benjamin Netanyahu defined a "red line" for Israel, determined by Iran’s amassing of 250 kilograms of uranium enriched to 20 percent. This amount will allow Iran to rapidly achieve further enrichment to 90 percent and the assembly of one atomic bomb. Over the last few months, the Iranians have been careful to stay away from this amount. Every few weeks they divert some of the 20 percent enriched uranium they produce into fuel rods used in a research reactor in Tehran.

Much of the enrichment to the 20 percent level takes place in the underground, well-fortified facility at Fordow. In contrast to past offers, the latest one made by the six powers did not demand a complete closure of the Fordow facility but only a suspension of its operations.

“Our goal is to make sure that the Fordow facility ceases to be a source of concern, and that is the key feature of our present offer," said the American official. “We would like to see the Iranians take some confidence-building measures with regard to further enrichment of uranium to 20 percent, to the Fordow installation and to the enriched uranium reserves they already possess."

In addition, the new offer does not insist on removing all of the 20-percent-enriched uranium from Iran and allows it to keep some of it for production of nuclear fuel for its research reactor in Teheran, which produces isotopes for medical use. The offer also calls for enhanced supervision of Iran’s nuclear facilities by the International Atomic Energy Agency. The powers demand to shorten the intervals between visits by inspectors in order to prevent Iran from surging ahead in their program without detection by the IAEA.

In exchange, the six powers will agree to ease the economic sanctions imposed on Iran and to commit to suspending imposition of further sanctions. However, the powers did not agree to suspend the oil embargo put in place by the European Union.

The American official noted that the impression is that the Iranians are seriously considering the offer. “We are cautiously optimistic, but the burden of proof lies with the Iranians, who have to respond to this offer in a serious manner," he said. He further noted that if Iran does not accept this offer and does not take steps to reduce its production of enriched uranium, international pressure on it will mount.

Over the last few days the Iranians have demonstrated a positive attitude to the upcoming negotiations, but still present a tough bargaining position. In Thursday's speech, Jalili said that “Iran expects the U.S. to change its behavior, and this will be tested in the coming negotiations. Anyone coming to negotiate should do so with reason and not with threats stating that all options are on the table."

The talks in Kazakhstan will commence on Friday morning and last until Saturday evening. Early next week, the head of the American negotiating team, Wendy Sherman, will arrive in Israel in order to update the national security advisor Yaakov Amidror on the talks.

Officials in Israel regard the negotiations in Kazakhstan with great scepticism. In talks held earlier this week with the Norwegian Foreign Minister Espen Barth Eide, Netanyahu said that he objects to Iran's continued development of nuclear weapons while talks were being conducted.

All other issues faced in the region "will be overshadowed if Iran believes it has a license to develop atomic weapons and I it pursues the development of these weapons," he said. "We have to make sure this doesn't happen."