ANDREA MITHCELL, MSNBC: There are reports from the negotiations that in fact Iran is now insisting on not having a written deal.



Talk about transparency, Congress is going to demand that -- They want it to be more ambiguous until the final technical details are worked out in June, probably to deal with their own political problems, selling this to their hard liners and at the same time keep centrifuges working at the underground facility.



Can we guarantee that the requirements you just laid out of inspections and not being able to secretly create a bomb are going to be met?



LEON PANETTA: Well, you know, one thing I’ve learned both at the CIA and as Secretary of Defense is that the Iranians can't be trusted. It’s for that reason that we have to make sure that we've taken strong steps to be able to make sure that they are not trying to do something in secret.



So, my concern obviously is that the more they maintain of their nuclear infrastructure in terms of centrifuges, the more they are allowed to maintain this hidden facility in which they were trying to do enriched fuel, the more temporary the agreement is, those are issues that obviously raise concerns.



I think I’m willing to let them continue these negotiations. I think it's important to do. I think it obviously is worth the effort. But I think the real test is going to be -- and the whole world will be looking at it, the test will be have we truly made sure that Iran can be stopped from developing a nuclear weapon. And to do that in my book demands transparency and demands accessibility so that we have a firm inspection regime that will guarantee they cannot do this.