Prime Minister Naftali Bennett warned the head of the International Atomic Energy Agency Friday that Israel was prepared to use it's "right to self-defense" to stop Iran's nuclear programme.

The comments came after IAEA chief Rafael Grossi met Bennett Friday morning during a whirlwind visit.

Bennett's warning is a reiteration of Israeli vows to do whatever it takes to stop Iran from obtaining a nuclear bomb. It comes with tensions rising over stalled efforts to revive a 2015 nuclear deal between Iran and world powers aimed at preventing Iran from developing such a weapon.

Bennett said in a statement that he has made it clear that Israel prefers diplomacy, but "it reserves the right to self-defense and to action against Iran in order to block its nuclear programme should the international community not succeed in the relevant time frame."

Grossi's visit came after the global nuclear watchdog on Monday said it still had questions which were "not clarified" despite long-running efforts to get Iran to explain the presence of nuclear material at three undeclared sites.

The issue of the sites is one of the remaining obstacles to reviving the 2015 deal which gave Iran relief from crippling economic sanctions in exchange for curbs on its nuclear activities. 

Experts consider Israel as the only nuclear power in the Middle East, though the country refuses to confirm or deny that it has such weapons.

Iran has always denied seeking a nuclear bomb.

Israel is staunchly opposed to the 2015 agreement which it perceives as a threat to its security.

In October Israeli Foreign Minister Yair Lapid said that, "If a terror regime is going to acquire a nuclear weapon, we must act." He added that Israel "reserves the right to act at any given moment in any way." 

This week the Israeli army held military exercise over the Mediterranean and in the Red Sea. Israeli media reported the exercise simulated a wide-scale attack on Iran, including on its nuclear facilities.

When questioned by AFP on Thursday, the army did not comment on the nature of the drills, but confirmed that it prepares and trains "continuously for several scenarios including threats from Iran".