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.

Ibrahem Alhaj, a member of the Syria Civil Defense first responders team, says he got to the scene of the suspected chlorine attack shortly after a helicopter dropped barrels containing what he said were four chlorine cylinders.

He says the cylinders fell in the crowded al-Sukkari neighborhood on Tuesday and that at least 80 civilians were transported to hospitals and treated for breathing difficulties. A video by the rescuers shows children crying and men coughing.

The report could not be independently verified and it was not clear how the activists determined that chlorine gas was released.