By Anees Barghouthy

JERUSALEM

 Former chief of Israel's Mossad intelligence agency has asserted that the understandings that have been reached between world powers and Iran on the latter's nuclear program include "positive" aspects.

Ephraim Halevy was quoted by the Israeli radio as saying that the framework agreement signed Thursday in Switzerland's Lausanne is "very detailed."

"The agreement states that the number of centrifuges at [Iran's] Natanz nuclear facility must be reduced and not to use new models of devices," he said.

"The agreement also stipulates that the Fordow facility would turn into a research and development facility for peaceful purposes," he added. "No fissile material will also be used in the facility for the next 15 years."

Halevy's remarks came despite calls by Israeli Prime Minister Benjamin Netanyahu for additional sanctions on Tehran in order to get "a better deal."

Speaking after a cabinet meeting on Friday, Netanyahu said the framework agreement would lend international legitimacy to Iran's nuclear program.

"The deal will not shut down a single nuclear facility in Iran, will not destroy a single centrifuge in Iran, and will not stop research and development on Iran's advanced centrifuges," Netanyahu said.

"On the contrary," he added, "the deal will legitimize Iran's illegal nuclear program. It will leave Iran with a vast nuclear infrastructure."

Netanyahu added that Israel would not accept any future agreement that did not include Iran's recognition of Israel's right to exist.

On Thursday evening, Iran and the P5+1 group of world powers (the U.S., China, France, Russia, the U.K. and Germany) unveiled a preliminary framework for talks aimed at curbing Tehran's nuclear program.

They have set themselves a June 30 deadline for reaching a deal.  

Following the announcement, U.S. President Barack Obama hailed the negotiations with Iran as "historic."

Netanyahu has repeatedly voiced his rejection of a nuclear deal with Iran, claiming such an agreement would endanger his country's security.