A rebel fighter raises his weapon after firing a missile Sunday toward Syrian government troops in the northern city of Aleppo. Syria's largest city has been the scene of heavy fighting for the past three months. Both sides control part of the city, and the fight has been a stalemate recently. Narciso Contreras/AP hide caption

itoggle caption Narciso Contreras/AP

An image taken from video obtained from the Shaam News Network, authenticated by AP reporting, shows attempts to rescue the wounded in Idlib, northern Syria following heavy bombing from military warplanes. Uncredited/ASSOCIATED PRESS hide caption

itoggle caption Uncredited/ASSOCIATED PRESS