Official Says US In Intense Negotiations With Iran

The U.S. ambassador to the United Nations says Washington and other veto-holding members in the U.N. Security Council are studying sanction options if Iran does not prove its nuclear program is for peaceful purposes.

The U.S. official, Susan Rice, also says the so-called P-5 + 1 is in a period of "intense negotiations" with Tehran but that Iran had a "finite period" to completely open its nuclear program to international inspections. She refused to set a deadline.

Rice said the United States had three options: to push sanctions through the U.N., to work with European allies to punish Iran, or to take unilateral action in conjunction with the other possible courses of action.

Rice spoke Sunday on NBC's "Meet the Press."