A Syrian military offensive backed by heavy Russian air strikes threatened to cut critical rebel supply lines into the northern city of Aleppo on Tuesday, while the warring sides said peace talks had not started despite a U.N. statement they had. U.N. envoy Staffan de Mistura announced the formal start on Monday of the first attempt in two years to negotiate an end to a war that has killed 250,000 people, caused a refugee crisis in the region and Europe and empowered Islamic State militants. But both opposition and government representatives have since said the talks had not in fact begun and fighting on the ground raged on without constraint. De Mistura acknowledged that a collapse of the Geneva talks was always possible. “If there is a […]