Syrian and Russian jets step up strikes on rebels after opposition seizes much of Aleppo CNNSyria’s Rebels Struck When Assad’s Allies Were Weakened and Distracted The New York TimesWhat Tulsi Gabbard Has Said About Syria's Assad as Insurgents Seize Aleppo NewsweekThe illusion of Assad’s grip on Syria shatters, as Russia, Iran and Hezbollah let their guard down CNNRussian, Syrian jets intensify bombing of Syria's rebel-held northwest Reuters