Switzerland- Iran and six major powers were exploring possible compromises to break an impasse in nuclear negotiations today, but officials cautioned they were unable to move on several sticking points.

The news came as Israel said the details of a possible agreement emerging from talks in Lausanne, Switzerland were worse than it feared.

In a significant development in talks aimed at securing a preliminary nuclear deal, several officials told Tehran had indicated a willingness to accept fewer than 6,000 nuclear centrifuges and to send most of its enriched uranium stockpiles for storage in Russia.

Western powers, on the other hand, were considering the idea of allowing Iran to conduct limited, closely-monitored enrichment-related work for medical purposes at an underground facility called Fordow, the officials added on condition of anonymity.

Iran had originally insisted on keeping in operation the nearly 10,000 centrifuges it currently uses, but said in November that Washington indicated it could accept around 6,000. Iranian officials say they had been pushing for 6,500-7,000.

The officials said all parts of an emerging nuclear deal were interrelated.

"Everything could still fall apart," a Western official told, adding that the talks could drag on to Tuesday, the self-imposed deadline for a framework agreement.

Another official said it was "more or less reality", but that nothing was set in stone yet.