Syria's cease-fire appeared on the brink of collapse on September 19 after a U.S.-led coalition air strike killed at least 62 Syrian government soldiers during the weekend and the city of Aleppo was hit by its first air raids in nearly a week.Correspondents say the barrage of strikes on rebel-held districts of Aleppo on September 18 risks reigniting battles in the city and could be the most serious threat to the cease-fire so far.
