Top Obama administration officials say Iran will come under extreme pressure to disclose its nuclear intentions when envoys from Tehran sit down on Thursday in Geneva with representatives of the United States and other world powers.
Secretary of State Hillary Clinton says Iran will have to prove without a doubt that its nuclear program is for peaceful purposes. "We don't believe that they can present convincing evidence it is only for peaceful purposes. But we are going to put them to the test on October 1," she said.
She says the fact that Iran sought to hide the construction of a second uranium enrichment plant calls Tehran's claims into question.
Clinton told the CBS television program, "Face the Nation" that the world is looking for hard evidence from Iran. "Words are not enough," she said. "They are going to have to come and demonstrate clearly to the international community what they are up to."
The secretary of state acknowledged that some of the current sanctions in place on Iran are porous. She said discussions are underway on how to make them broader and deeper.
In a series of Sunday morning television interviews, Secretary of Defense Robert Gates downplayed the notion of military action. He told ABC's "This Week" program he favors tough sanctions, if diplomacy fails. "Their economic problems are difficult enough that I think that severe sanctions would have the potential of bringing them to change their policies," he said.
On the "Fox News Sunday" program, California Democrat Diane Feinstein - Chairwoman of the Senate Select Committee on Intelligence - said Iran has a big choice to make. "I think this is the moment of decision for Iran," she said. "Iran can either make itself a pariah or it can recognize that it has much more to gain by eliminating any potential military aspect of a nuclear program."
Appearing on the same program, Missouri Republican Senator Kit Bond said that the time for enhanced sanctions is now. He said he has not seen anything that would convince him that Iran is about to change its behavior. And he pointed to Tehran's decision to test missiles on Sunday as a dramatic example. "Today's action in firing the missiles is really a poke in the eye to those who think that diplomatic efforts and agreements and inspections are going to change the way that Iran is going," he said.
An initial Iranian test on Sunday involved short-range missiles. A long-range missile test is expected on Monday.