'Important issues' remain in nuclear talks: Iranian source

(L-R) Iranian officials Abbas Araqchi, Mohammad Javad Zarif, Majid Takht-Ravanchi and Hossein Fereydoun stand on a balcony at the Palais Coburg Hotel in Vienna on July 11, 2015 (AFP Photo/Joe Klamar) (AFP)

Vienna (AFP) - Iran and major powers still have "important issues" to resolve before they can nail down a historic nuclear accord, a source close to Iranian negotiators said Monday amid expectations a deal was close.

"There remain some important issues and we are working hard to resolve them," the source told AFP on condition of anonymity on the 17th day of talks in Vienna.