The fatalities included seven children, the Britain-based watchdog said.
Three rescuers were killed after Russian jets hit their vehicle in the northern part of the province of Hama in central Syria.
A child was also killed in a government air attack in Idlib's village of Kafr Eweid, the observatory said.
Since late April, the forces of Syrian President Bashar al-Assad, supported by Russian air power, have been waging a massive campaign against rebels in the provinces of Hama and Idlib, the last major opposition strongholds in the country.
The offensive has so far killed at least 828 civilians, according to the observatory estimates.
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