UNITED NATIONS - The UN special envoy for Yemen on Monday announced a plan for a ceasefire in Yemen starting on Wednesday night, a U.N. statement said. Special Envoy Ismail Ould Cheikh Ahmed has received assurances from all Yemeni parties for a ceasefire to begin at 23:59 Yemen time on Wednesday, for an initial period of 72 hours, subject to renewal, the statement said.