A Syrian rebel fighter is shown in the northeastern Syrian border town of Ras al-Ayn on Nov. 11, several days after the rebels captured it. The rebel takeover has created friction with the town's Kurdish population. Murad Seezer/Reuters/Landov hide caption

itoggle caption Murad Seezer/Reuters/Landov

Moaz al-Khatib, a Muslim cleric, is the leader of the newly formed opposition group, the Syrian National Coalition. The opposition is working to build support inside Syria through Facebook and other social media. Karim Jaafar/AFP/Getty Images hide caption

itoggle caption Karim Jaafar/AFP/Getty Images

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