Main opposition pulls out of the formal talks in Geneva a week ago

The United Nations mediator on Thursday called on the leaders of the United States and Russia to salvage the "barely alive" two-month-old cease-fire in Syria and revitalize the damaged peace process.

UN Special Envoy Staffan de Mistura voiced deep concern at the truce unraveling in Aleppo and at least three other hotspots, although he saw some narrowing of positions between the government and opposition visions of political transition.