Rescuers in Syrian city of Maarat al-Numan are picking through the rubble after what they say was a Syrian military airstrike on a market Sunday.
At least six were killed while the Syrian Observatory for Human Rights puts the death toll at 11.
Syria's famed White Helmet rescuers pulled a man and young boy from under a pile of rocks and dust, saying they expect to find more victims.
Maarat al-Numan is in Syria's rebel-controlled Idlib province, which borders Turkey.
Turkish forces have launched what President Recep Tayyip Erdogan calls a "serious" operation in Idlib, parts of which are in the hands of al-Qaida linked extremists formerly known as the Nusra Front.
The operation is, in part, aimed at enforcing a de-escalation zone in Idlib, as agreed to by Turkey, Iran, and Russia during talks in Kazakhstan. The militants oppose such a zone.
Turkey also says establishing a zone would prevent what it calls a "terror corridor" that it says could allow Kurdish fighters battling the Syrians to link up with separatists inside Turkey.