The 2015 deal limited Iran’s enrichment of uranium to make it harder for Tehran to develop material for nuclear weapons, in return for a lifting of international sanctions against Tehran.

But it has eroded since 2018 when then-president Donald Trump withdrew the US and reimposed far-reaching sanctions on Iran.

“The emerging deal, as it seems, is highly likely to create a more violent, more volatile Middle East,” Bennett said in a speech in Jerusalem to Jewish American leaders.

The aim of the nuclear talks in Vienna is to return to the original bargain of lifting sanctions against Iran in exchange for restrictions on its nuclear activities that extend the time it would need to produce enough enriched uranium for an atomic bomb if it chose to.

Iran says its nuclear ambitions are peaceful.

Bennett said the biggest problem in current negotiations was the possibility of the shorter timeline – two and a half years – before Iran could freely operate advanced centrifuges, since the original timeline may not be extended.

“Israel will not accept Iran as a nuclear threshold state,” he said, reiterating a long-standing position, at the Conference of Presidents of Major American Jewish Organizations. “Israel will always maintain its freedom of action to defend itself.”