Israel army chief says Iran not building nuclear bomb "I think the Iranian leadership is comprised of very rational people," Gantz said. But I agree that such a capability in the hands of Islamic fundamentalists, who at some moments may make different calculations, is a dangerous thing. In an interview with CNN on Tuesday, Netanyahu said he wouldn't want to bet "the security of the world on Iran's rational behaviour." A "militant Islamic regime," he said, "can put their ideology before their survival." Iran this month began negotiations over its nuclear programme with six world powers for the first time in more than a year. Either Iran takes its nuclear program to a civilian footing only, or the world, perhaps us too, will have to do something. We're closer to the end of the discussions than the middle," Gantz said. Western diplomats greeted Iran's first meeting with the United States, Russia, China, Germany, France and Britain with cautious optimism, and the two sides agreed to meet again in Baghdad on May 23. But Israeli Defence Minister Ehud Barak last week voiced scepticism that negotiations will curb Tehran's nuclear ambitions. Netanyahu said the hiatus in talks awarded the Iranians a "freebie" - more time to enrich uranium. Gantz said international pressure on Iran "is beginning to bear fruit, both on the diplomatic level and on the economic sanctions level." Netanyahu said on CNN the sanctions were "certainly taking a bite out of the Iranian economy but so far they haven't rolled back the Iranian programme or even stopped it by one iota." In an interview that appeared on Wednesday in Israel's Maariv newspaper, President Shimon Peres echoed doubts voiced by some former top Israeli security officials over whether a military strike against Iranian nuclear facilities would be effective. You could also ask whether military sanctions would work. Nothing is clear. Therefore it makes more sense to start with economic, political and moral sanctions, without taking military sanctions off the table," Peres said.