BEIRUT/MOSCOW (Reuters) - U.S.-led coalition air strikes reportedly killed dozens of Syrian soldiers on Saturday, endangering a U.S.-Russian brokered ceasefire and prompting an emergency U.N. Security Council meeting as tensions between Moscow and Washington escalated. A damaged wall of a school is pictured in rebel-held Ain Tarma, eastern Damascus suburb of Ghouta, Syria September 17, 2016. REUTE