Insurgents said to have launched chlorine shells into the government occupied city, although rebel group leaders deny the claims.
ADVERTISEMENTMore than 100 people have been injured in Aleppo after an alleged toxic gas attack by insurgents.
The shelling caused scores of people to suffer maladies ranging from fainting to severe breathing problems.
It marks the highest casualty toll in Aleppo since government forces wrestled the city back from rebels nearly two years ago.
A leader of the National Liberation Front rebel group dismissed claims that chemical weapons were used, saying the coalition of insurgent forces does not possess poisonous gas.
Meanwhile, nine people were in a village near the rebel stronghold of Idlib in an airstrike by Russian warplanes - the first since September.
The attack was apparently in retaliation to the earlier strikes in Aleppo.