Iran's top nuclear official has signaled that Iran could compromise on uranium enrichment by eventually only enriching to the low level needed for power.

Fereidoon Abbasi, head of the Iranian Atomic Energy Organization, told state television on Sunday that Iran doesn't need uranium enriched above the 20 percent level needed for the Tehran research reactor which produces medical isotopes. Once there's enough supply, he said, enrichment could be dropped it to the 3.5 percent level needed for nuclear power (weapons-grade uranium is more than 90 percent enriched).

"Based on our needs and once the required fuel is obtained, we will decrease the production and we may even totally shift it to the 3.5 percent," Abbasi said, according to Iran's Press TV.

"We are going to produce and store [20 percent enriched uranium] to some extent in order to provide fuel for Tehran's [research] reactor for a few years or to predict fuel needs of another research reactor," he said.

The comments come days before Iran begins a new round of talks on Saturday in Istanbul with the so-called P5+1, the five permanent members of the United Nations Security Council and Germany. The last round of talks fell apart in January 2011. Since then, the United States and European Union have imposed strict economic sanctions and an oil embargo on Iran.

The P5+1 nations are expected to ask for Iran to shut down the Fordow enrichment facility buried deep under a mountain as well as to stop production and ship out uranium enriched to 20 percent, according to a report in the New York Times.

But comments today by Iran's foreign minister raised doubts over any concessions.

"Setting conditions before the meeting means drawing conclusions, which is completely meaningless and none of the parties will accept conditions set before the talks," Ali Akbar Salehi said.

On Sunday, Iranian President Mahmoud Ahmadinejad defended Iran's nuclear program, saying it would not go beyond the terms of the nuclear Non-Proliferation Treaty and lashing out at the countries opposed to the program.

"Many of these very countries that are seeking to stop the progress of the Islamic Republic themselves have atomic weapons and they have also created the Zionist regime [Israel] and equipped it with the atomic bomb," he said.

Iran has long insisted that its nuclear program is only for peaceful purposes while the U.S. and its supporters believe Iran would like to build a nuclear weapon. President Obama has repeatedly said that all options are on the table to deal with Iran while Prime Minister Benjamin Netanyahu of Israel, who has been weighing a military strike on Iran's nuclear facilities, said Sunday that he wants all Iranian uranium enrichment to stop and all its material removed.

However, in a contradictory statement, Israeli Defense Minister Ehud Barak said Sunday that Iran could keep "a quantity of several hundred kilograms which would not allow for the continued enrichment for weapons or a nuclear facility."

After several weeks of disagreement over where - and whether - this week's talks would be held, Iran's semi-official news agency Fars reported Sunday that a first round would be held starting Saturday in Istanbul, followed by a second round in Baghdad "in case of progress."