Blood stains are seen in a destroyed classroom at the Ain Jalout school following reported air strikes by Syrian government forces in the Ansari district of the northern city of Aleppo on April 30, 2014. The air raid on the rebel-held neighbourhood, killed at least 18 people, 10 of them children, a monitoring group said. The government's use of barrel bombs -- unguided munitions usually dropped from altitude to avoid ground fire -- has come in for particular criticism from human rights watchdogs because of their indiscriminate toll on civilians.    AFP PHOTO/AMC/ZEIN AL-RIFAI-RIFAI        (Photo credit should read ZEIN AL-RIFAI/AFP/Getty Images)