With the second round of nuclear talks between Iran and the six major powers due to begin in Tehran on Wednesday, senior Israeli sources say Jerusalem may be more flexible about Iranian low-level uranium enrichment than it is currently willing to let on.

Though Israel has been expressing zero flexibility regarding a possible deal with Iran, Defense Minister Ehud Barak a few weeks ago issued a written statement that Israel would consent to Iran´s continuing enrichment of uranium to a low level of 3.5 percent, as well as to allowing a few hundred kilograms of 3.5-percent enriched uranium to remain in that country.

"Enrichment percentage" refers to the degree to which natural uranium has been enriched with the U-235 isotope - an isotope which can sustain a chain reaction of nuclear fission. Reactor-grade uranium is enriched to about 3 to 4 percent, while weapons-grade uranium is 90 percent enriched. However, crude nuclear weapons can be built with uranium enriched to as low as 20 percent.

A senior Israeli source said that Barak´s remarks, which were shared in private conversations with U.S. officials, contradict the tough line being presented by Prime Minister Benjamin Netanyahu, who has demanded that Iran stop all uranium enrichment and give up any enriched uranium it has in its possession.

More recently, Barak has publicly toed Netanyahu´s line, but the assessment is that the things the defense minister said in his statement represent the limited concession Israel is willing to make to enable the P5 +1 powers - the United States, Russia, China, France, Britain and Germany - to continue discussions with Iran.

It seems now that those countries and Iran are seeking an interim agreement, under which Iran would stop enriching uranium to a level of 20 percent. This would mean that the enrichment process at the reinforced underground facility in Fordo, near Qom, would essentially stop. It would also mean Iran would have to give up some 100 kilograms of 20-percent enriched uranium it already has.

In return, the six powers would cease efforts to impose new sanctions on Iran: While the European Union´s oil embargo will go into effect on July 1 as scheduled, as will American sanctions against Iran´s central bank - no additional limitations will be imposed. In addition, Iran would be sent a shipment of nuclear fuel rods for its research reactor.

A senior Israeli official said on Sunday that publicly, Israel will continue to talk tough on Iran to make sure the six powers don´t rush into an agreement with Tehran.

"We´re the indicator on the right," the official said. "We are aware that the powers want to come to an agreement with Iran, which is why we are warning against euphoria. A good atmosphere during the negotiations with Iran is liable to be addictive."

Sources note that it is clear that as long as negotiations between Iran and the six powers are continuing, the Israeli option of attacking Iran´s nuclear facilities remains in abeyance. In such a situation, Israel can do little except warn the P5 +1 against falling into an Iranian honey trap.

At a press conference on Sunday with U.S. Homeland Security Secretary Janet Napolitano, Foreign Minister Avigdor Lieberman said that Israel still doesn´t see any willingness on Iran´s part to give up its nuclear ambitions.

"From Iran´s perspective the talks are a deception and an effort to buy time," Lieberman said. "I don´t think the international community has any illusions about Iranian plans or Iran´s readiness to abandon its nuclear military plans." (© Copyright 2012 Ha´aretz 05/21/12)