Children were among 14 people killed when missiles hit a hospital and school in a rebel-held Syrian town near the Turkish border.
Scores more were injured in the strikes on Azaz where tens of thousand of refugees had fled to escape heavy fighting between Syrian troops and opposition militias.
Meanwhile, in a separate raid, Médecins Sans Frontières (MSF) said a hospital supported by the aid group had been “deliberately” targeted in a suspected Russian airstrike.
At least nine civilians, including a child, were killed in the attack on Maaret al Numan, about 170 miles north of the capital Damascus.
The latest deadly strikes comes after Russia said a limited ceasefire due to come into effect at the end of this week did not apply to its airstrikes, which have paved the way for major gains by the Syrian army.
Supported by Russian airpower, government troops have nearly encircled Aleppo, Syria’s second city. Speaking in the capital Damascus last week, Syrian President Bashar al Assad vowed to retake the entire country.
At the same time, Turkey has vowed not to let Azaz fall to Syrian Kurdish fighters. Turkish security forces have again fired on Kurdish militia after a border post was attacked.