shortly after the attack. four days ago the u.n. security council said they would take more action if chlorine was used as a weapon in syria. there have been three others since 2011. in aleppo there is outrage at the united nations. protesters took to the streets angry over a failed plan to freeze the fighting. we report four years of war and the lack of a meaningful peace process is not helping. >> reporter: this is what the united nations was hoping to stop but it has failed to stop the conflict in syria's second largest city. barrel bombs have killed hundreds over recent months and they continue to fall in populated areas of rebel control. >> reporter: they populated the city. more than a million used to live in the rebel area. now there is 300,000. there was a mass exodus because there was a time when dozens of people were dying every day. >> reporter: the syrian