United Nations Special Envoy to Yemen Martin Griffiths (C) meets with Yemen's internationally-backed President Abdu-Rabbu Mansour Hadi (R) and Prime Minister Ahmed Obeid bin Daghr in Aden, Yemen, on June 27, 2018. Martin Griffiths arrived Wednesday in the southern port city of Aden to broker a ceasefire between the Saudi Arabia-backed government forces and Shiite Houthi rebels. (Xinhua/Ismail Rabidhy)