ISTANBUL -- The U.S. military's admission this week that an airstrike against extremists last year in Syria killed two children is too little and too late for many Syrians, hardening a deep distrust of U.S. efforts in the war-ravaged country. “It’s not surprising at all,” Syrian activist Abdulla Sallom said over a weak Skype connection from Kafranbel, a northern city in the Idlib countryside currently under the control of non-extremist forces battling the Assad regime.