Progress has been reported at Iranian nuclear talks.
U.S. Secretary of State John Kerry met with Iranian Foreign Minister Mohammad Javad Zarif and European Union foreign policy chief Catherine Ashton in Vienna on October 15 for the latest round of high-level negotiations.
An unnamed U.S. official said the sides were "chipping away at some of the issues," but added that much work lay ahead.
Iran and six world powers -- the United States, France, Germany, China, Russia, and Britain -- are facing a November 24 deadline to reach a deal, although both Tehran and Moscow have indicated that more time may be required.
The negotiations center on curbing Iran's nuclear activities in exchange for the lifting of sanctions.
The West suspects Iran's nuclear program may be aimed at developing nuclear weapons, something Tehran denies.