An Israeli official said that "there's never a 100 percent guarantee," but "a nuclear disaster" should "not happen."

When Israel launched its series of strikes against Iran last week, it also issued a number of dire warnings about the country’s nuclear program, suggesting Iran was fast approaching a point of no return in its quest to obtain nuclear weapons and that the strikes were necessary to preempt that outcome.

Israeli strikes on Natanz, Fordow and Isfahan pose little regional radiation risk but could release plumes of toxic chemicals, experts said.