US President Barack Obama has strongly allayed Israeli fears that Iran might acquire nuclear weapons the way Pakistan and North Korea did,saying the verification mechanism around Tehrans atomic programme is unprecedented and makes it difficult to cheat. With respect to Pakistan,there was never the kinds of inspection regimes and international sanctions and UN resolutions that were in place, Obama said in response to a question at the 10th annual Saban Forum meeting here. Obama said that by the time the US got an agreement with North Korea,Pyongyang already had acquired a nuclear weapon. We have been able to craft an international effort and verification mechanism around the Iranian nuclear programme that is unprecedented and unique. That doesnt mean its easy. And thats why we have to take it seriously, said Obama when asked about the failure of the United States in the past to prevent countries like Pakistan from acquiring nuclear weapons. With best intentions and all out efforts,(the former US) President (Ronald) Reagan vowed that Pakistan wouldnt go nuclear. Didnt happen. With the best intentions and all out efforts,President Clinton vowed that North Korea wont go nuclear. Why is this nuclear deal different than any other? the President was asked. Obama acknowledged that achieving the goals would be tough. Its important for everybody to understand this is hard. Because the technology of the nuclear cycle,you can get off the Internet; the knowledge of creating nuclear weapons is already out there. And Iran is a large country and it is a relatively wealthy country,and so we have to take seriously the possibility that they are going to try to get a nuclear weapon. Thats what this whole exercise is about, he argued. I think one of the things that Ive repeatedly said when people ask,why should we try to negotiate with them,we cant trust them,were being naive,what I try to describe to them is not the choice between this deal and the ideal,but the choice between this deal and other alternatives, he said. If I had an option,if we could create an option in which Iran eliminated every single nut and bolt of their nuclear programme,and foreswore the possibility of ever having a nuclear programme,and,for that matter,got rid of all its military capabilities,I would take it, he said. Iran and P5+1 last month agreed on a historic deal that freezes key parts of Tehrans nuclear programme in exchange for temporary relief on some economic sanctions.