U.N. mediator Lakhdar Brahimi during his news conference Friday in Geneva. Martial Trezzini/EPA/Landov hide caption
Lakhdar Brahimi
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
In Aleppo, Syria, an opposition fighter shouted as he manned a position on Monday. Fabio Bucciarelli/AFP/Getty Images hide caption
Lakhdar Brahimi, right, joint special representative for Syria, arrives at closed door consultations regarding the situation in Syria at the Security Council at United Nations headquarters on Monday. David Karp/AP hide caption