U.S., Russia agree Syria truce plan; rebels see flaws

By Arshad Mohammed and Tom Perry WASHINGTON/BEIRUT (Reuters) - The United States and Russia announced plans for a 'cessation of hostilities' in Syria that would take effect on Saturday but exclude groups such as Islamic State and al Qaeda's Nusra Front, a flaw immediately highlighted by Syrian rebels. Monday's agreement, described by a U.N. spokesman as "a first step toward a more durable ceasefire", is the fruit of intensive diplomacy between Washington and Moscow, which back opposing sides in