BEIRUT (AP) — Syrian activists and rescue workers in the rebel-held part of the contested city of Aleppo are saying that government warplanes have dropped suspected chlorine bombs on a crowded neighborhood, injuring dozens. The report could not be independently verified and it was not clear how the activists determined that chlorine gas was released. Accusations involving use of chlorine and other poisonous gases are not uncommon in Syria's civil war, and both sides have denied using them while blaming the other for using it as a weapon of war. UN confirms previous chlorine attacks

The Assad regime has been repeatedly accused of using chlorine gas as a chemical weapon, and a UN investigation in August found that regime forces had twice carried out chlorine attacks. It said at least 71 people, including 37 children and 10 women, were treated for breathing difficulties and dry cough, and that "a strong smell of chlorine emanated from their clothes." Most were discharged after several hours, but ten people remained in intensive care, including a pregnant woman in her last trimester whose unborn child was showing a weak pulse, the committee claimed. Ibrahem Alhaj, a member of the Syria Civil Defense first responders' team, also known as the White Helmets, said he got to the scene in the crowded al-Sukkari neighborhood shortly after a helicopter dropped barrels containing what he said were four chlorine cylinders. The video also shows a boy being washed with a hose by rescuers after being pulled from the rubble as the sirens of ambulances wail around him. The UK-based Syrian Observatory for Human Rights also reported the attack, saying that medical sources accused regime warplanes of pounding the Sukkari neighborhood with barrel bombs "laden with poison gas." A United Nations and Organization for the Prohibition of Chemical Weapons inquiry seen by Reuters last month found that Syrian government forces were responsible for two toxic gas attacks in 2014 and 2015 involving chlorine. Expert sees resurgence in chemical weapons

Hamish de Bretton-Gordon, a chemical weapons expert who is an adviser to nongovernmental organizations in Syria and Iraq, said chlorine gas could be deadly, and was a powerful psychological weapon.
A chlorine attack in Aleppo on Tuesday injures more than 100 people. The blast from barrel bombs dropped kills one person.