TEHRAN — Iran’s nuclear chief is hinting at a compromise offer from Tehran ahead of negotiations with world powers this week over the country’s controversial atomic program.

At the core of the dispute is the issue of uranium enrichment. The West fears Tehran is seeking an atomic weapon, which the country denies. Uranium has to be enriched to more than 90 percent to be used for a nuclear weapon.

Iran’s nuclear chief Fereidoun Abbasi said Tehran could stop its production of 20 percent enriched uranium needed for a research reactor, and continue enriching uranium to lower levels for power generation.

Abassi told state TV late Sunday that this could take place once Iran has stockpiled enough of the 20 percent enriched uranium.

The negotiations are to take place in Istanbul on Friday.

However, Prime Minister Benjamin Netanyahu said on Monday that Iran must stop all enrichment of uranium, both 20% and 3%, and move all enriched material out of its territory.

Netanyahu also demanded that Iran dismantle its facility in Qom that, he said, is illegal. “It’s possible to give Iran alternative material for peaceful purposes,” Netanyahu said.

No issue looms larger ahead of Friday’s summit than uranium enrichment, which Iran is permitted to do under a UN treaty overseeing nuclear advances. The US and others fear the labs could be used to make weapons-grade material. Iran says it nuclear program is only for energy and medical research.

But there have been some tiny cracks in the wall of distrust between Washington and Tehran that could at least offer some toeholds in the talks.

Iran’s Supreme Leader Ayatollah Ali Khamenei gave a rare nod of approval last month toward US President Barack Obama’s assertion that there is still room for diplomacy. Washington now says they want to hear further details about Khamenei’s pledge that Iran would never seek nuclear arms.

“Diplomacy has not reached a deadlock,” said Iranian lawmaker Heshmatollah Falahatpisheh, a conservative member of parliament’s foreign policy and national security committee.

However, he echoed the common stance among Iranian officials that Western demands to halt uranium enrichment are a dead end.

What could get traction — suggested the hardline newspaper Kayhan — is a so-called “enrichment level stabilization.” That means halting the 20 percent enrichment, the highest level acknowledged by Iran, and continuing with lower levels of about 3.5 percent needed for ordinary reactors.

The 20 percent material, which is used for medical isotopes for cancer treatments and other research, is several steps closer to the more than 90 percent level needed for a nuclear warhead.

“Americans have always made big demands and then retreated step by step as they saw that it’s not possible to achieve them,” Kayhan wrote in an editorial Sunday.

Mehdi Sanaei, a moderate lawmaker, said a possible bargaining position could be an agreement to temporarily stop 20 percent enrichment in exchange for lifting some economic sanctions.

Israel’s defense minister appeared to focus on the 20 percent enriched uranium as a key goal of the talks. Ehud Barak told CNN on Sunday that Iran should ship all of its uranium enriched at the 20 percent level to a “trusted” neighboring country. Anything short of that would “be a total change of direction for the worse,” he said.

Copyright 2012 The Associated Press.