US Secretary of State John Kerry sought on Sunday to offer assurances to Israel over the nuclear deal with Iran, saying that the agreement would make the Jewish state safer over the next six months.

"Israel is threatened by what has been going on in Iran," Kerry told CNN.

"But I believe that from this day - for the next six months - Israel is in fact safer than it was yesterday because we now have a mechanism by which we are going to expand the amount of time in which they (the Iranians) can break out (toward making a nuclear bomb). We are going to have insights to their program that we didn't have before," he added.

"I believe that Israel in fact will be safer, providing we make sure that these ... sanctions don't get lifted in a way that reduces the pressure on Iran - and we don't believe they will be, there's very little sanctions relief here - that the basic architecture of the sanctions stays in place," Kerry said.