Regime bombardment has killed 18 civilians in the last major region outside government control in northwest Syria over the past 48 hours, a war monitor said on Saturday.
Artillery and rocket fire launched by regime forces took the lives of eight children, seven women and three men in the Idlib region, the Syrian Observatory for Human Rights said.
The deadly bombardment hit the towns of Maaret Al Noman and Khan Sheikhun, said the Britain-based monitor, which relies on sources inside Syria for its information.
Idlib region is mainly controlled by Hayat Tahrir Al Sham, a Syrian group formerly linked to Al Qaeda, after they last month pushed back smaller, Turkey-backed rebel outfits.
Since September, the region has been protected from a massive regime offensive by a ceasefire deal brokered by regime ally Russia and rebel backer Turkey.
But sporadic regime bombardment has continued to hit the region, and hundreds of missiles rained down on Maaret Al Noman, Khan Sheikhun, and other areas on Friday and Saturday.
Almost eight years into Syria's grinding civil war, President Bashar Al Assad's regime controls around two-thirds of the country.
His army and allied fighters have made great gains against rebels and extremists since Russia's military intervened on the side of Damascus in 2015.
The war started in 2011 with the brutal repression of anti-Assad protests, and has since spiralled into a complex conflict involving world powers that has killed more than 360,000 people.
Friday and Saturday's deadly bombardment comes as the world waits for US-backed forces to expel ISIS from a final holdout in eastern Syria, marking the end of the group's self-declared "caliphate".