The attacks targeted residential areas in the towns of Jisr al Shughur, Khan Shaykhun, Maar Shoreen, Hantoteen and Ain al Bardeh in Idlib province, according to an Anadolu Agency correspondent on the ground.
At least 11 civilians were killed and 14 others injured in fresh regime air strikes in the de-escalation zones in northwestern Syria on Tuesday, a war monitor said.
Three children were among 10 civilians killed in the village of Maar Shureen in the south of Idlib province, said the Syrian Observatory for Human Rights.
Regime forces have also been locked in battle with Daesh and allied rebels on the edges of the bastion, which is held by Syria's former Al Qaeda affiliate Hayat Tahrir al Sham, including the north of Hama province.
Turkey and Russia agreed last September to turn Idlib into a de-escalation zone in which acts of aggression are expressly prohibited.
The Syrian regime, however, has consistently broken the terms of the ceasefire, launching frequent attacks inside the de-escalation zone.
A buffer zone planned under that accord was never fully implemented, and the region has seen an uptick in violence.
Syria has only just begun to emerge from a devastating conflict that began in early 2011 when Bashar al Assad's regime cracked down on demonstrators with unexpected severity.
Syria's war has killed a total of more than 370,000 people and displaced millions since it started in 2011 with a brutal crackdown on anti-government protests.