United Nations Envoy for Syria Staffan de Mistura (L) chats with Syria's President Bashar al-Assad during a meeting, in Damascus September 11, 2014, in this picture released by Syria's national news agency SANA. REUTERS/SANA/Handout via Reuters (SYRIA - Tags: POLITICS) ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING