"We've said that there are three key aspects involved here for Iran to meet its obligations. They need to implement -- sign and implement the additional protocol; cooperate fully with the IAEA; and once and for all, suspend its uranium enrichment and reprocessing activities," the spokesman said, referring to the International Atomic Energy Agency.

"If they do that, that would be, certainly, positive steps in the right direction. And we appreciate the efforts of the Europeans last week to get the Iranians to commit to doing that. But now they need to follow through on what they've committed to do and meet their international obligations," he added.

Iran soon will send the IAEA a letter indicating it plans to sign the additional protocol to the Non-Proliferation Treaty, said Iran's representative for the IAEA, Ali Akbar Salehi.

By signing it would agree to submit to virtually unannounced inspections of sites on its territory, whether previously declared or not.

The IAEA also has given Iran until October 31 to supply proof it is not making a nuclear weapon. If it misses the deadline it could be hit with sanctions.

Asked about the deadline, McClellan said "well, the deadline set out be the IAEA, I don't have the exact details of what that is within there. They need to do all three of these things is what they need to do. Those are essential that they meet all three of those obligations."

WAR.WIRE