UN Special Envoy for Syria Staffan de Mistura (C) arrives at Palais des Nations in Geneva, Switzerland, on Feb. 26, 2017. The UN-mediated latest round of intra-Syrian peace talks went into the fourth day in Geneva on Sunday. The deadly terrorist attack in central Syria on Saturday threatened to thwart efforts to wrest a political solution at peace talks in Geneva. (Xinhua/Xu Jinquan)