A man carries a young girl who was injured in a reported barrel-bomb attack by government forces on June 3, 2014 in Kallaseh district in the northern city of Aleppo. Some 2,000 civilians, including more than 500 children, have been killed in regime air strikes on rebel-held areas of Aleppo since January, many of them in barrel bomb attacks. AFP PHOTO / BARAA AL-HALABI (Photo credit should read BARAA AL-HALABI/AFP/Getty Images)
A Syrian man reacts while standing on the rubble of his house while others look for survivors and bodies in the Tariq al-Bab district of the northern city of Aleppo on February 23, 2013. Three surface-to-surface missiles fired by Syrian regime forces in Aleppo's Tariq al-Bab district have left 58 people dead, among them 36 children, the Syrian Observatory for Human Rights said on February 24. AFP PHOTO/PABLO TOSCO (Photo credit should read Pablo Tosco/AFP/Getty Images)
