AKIPRESS.COM - Iran and six world powers tried to break an impasse in nuclear negotiations on Sunday, but officials cautioned that attempts to reach a preliminary deal by a deadline in two days could yet fall apart.

The two sides explored compromises in areas including numbers of centrifuges used to enrich uranium that Iran could operate, and its nuclear enrichment work for medical research.

But Israel, which feels especially threatened by the possibility of a nuclear-armed Iran, said details of a possible framework agreement emerging from the talks in Lausanne, Switzerland, were even worse than it feared.

Foreign ministers from the six countries will hold ‎the first full meeting with Iran's foreign minister on Monday morning.

German Foreign Minister Frank-Walter Steinmeier said there had been "some progress and some setbacks in the last hours".

"I can't rule out that there will be further crises in these negotiations," he told Reuters.

The United States, Britain, France, Germany, Russia and China want more than a 10-year suspension of Iran's most sensitive nuclear work. Tehran, which denies it is trying to develop a nuclear weapons capability, is demanding an immediate end to international sanctions that are crippling its economy.

A Western diplomat said duration could be traded off if there were real efforts on some key parameters.