Suspected Russian airstrikes have killed 32 civilians, half of them women and children, the Syrian Observatory for Human Rights has said.
Observatory head Rami Abdel Rahman told the AFP news agency the jets bombed Raqqa, the self-declared capital of Islamic State's caliphate.
The warplanes also bombed the towns of Azaz and al Bab in Aleppo province, Mr Rahman said.
Six children and 11 women were among the dead, with dozens of people wounded, according to the British-based monitoring group.
The death toll in Raqqa included two rescue workers, according to Mr Rahman, who added no suspected militants were killed in the three areas hit.
Refugees fleeing the city said the militants' grip there is weakening as a result of coalition airstrikes.
Russia has been carrying out airstrikes on armed opposition groups throughout Syria for almost three months.
Moscow's campaign has been criticised by the West and rebels fighting Syrian President Bashar al Assad for targeting non-jihadist groups and causing civilian casualties.
The Observatory says it distinguishes between airstrikes carried out by Syrian, Russian and US-led coalition aircraft by looking at flight patterns, as well as the type of planes and ordnance used.
It identifies those killed through its network of activists, medical workers at local hospitals and fighters on the ground.