"An (aerial) attack using explosive-laden barrels over the Sakhur, Ard al-Hamra and Haydariyeh districts (of eastern Aleppo) killed 22 people, among them 14 children and an 18-year-old boy," said the Britain-based Observatory.
The Aleppo Media Centre (AMC), an activist network on the ground, reported several helicopter attacks on rebel-held areas of the city.
Once Syria's commercial capital, Aleppo has suffered massive destruction since a rebel offensive in July last year.