The number of people killed by barrel bombs dropped by government aircraft in the Syrian city of Aleppo on Sunday has risen to more than 70, activists say.
The Syrian Observatory for Human Rights said 28 children were among those who died in the rebel-held areas affected.
The opposition Aleppo Media Centre called the raids "unprecedented".
Rebels have asked civilians to move away from state security buildings in government-held parts of Aleppo, saying they will be targeted in retaliation.
In Sunday's raids, explosive-filled cylinders or oil barrels were reportedly rolled out of helicopters as they flew over the Sakhur, Ard al-Hamra and Haydariya areas of Syria's second city.