At least 25 people have died in a third consecutive day of Syrian government air strikes and shelling on rebel-held parts of Aleppo, activists say.
Eight besieged eastern districts were reportedly bombarded, as government forces stepped up an offensive.
A three-week moratorium on air strikes declared by the government and its ally Russia came to an end on Tuesday.
Meanwhile, another 20 people were killed in car-bomb attack in the rebel-held town of Azaz, north of Aleppo.
Both rebel fighters and civilians were among the dead, a senior official in the rebel Nour al-Din al-Zinki Movement told AFP news agency.
Yasser al-Yousef said the attack had targeted a security office belonging to his faction and that it "bore the hallmarks" of the jihadist group Islamic State (IS), to which it is fiercely opposed.