The Syrian Observatory for Human Rights said at least eight children were among the dead in the raids on suspected Daesh targets.
A barrage of US-led coalition air strikes killed 29 civilians on Wednesday in Syria's Raqqa, half of which is still held by Daesh, a war monitor said.
"At least eight children are among the dead," said Syrian Observatory for Human Rights chief Rami Abdel Rahman.
Backed by the US-led coalition, the Syrian Democratic Forces (SDF) have waged a months-long offensive on Raqqa and have successfully captured half the city.
With Wednesday's deadly raids, at least 325 civilians, including 51 children, have died in the city since the SDF penetrated Raqqa less than two months ago, according to the Observatory.
Tens of thousands of civilians have fled the escalating violence in recent months, but the United Nations estimates that up to 50,000 people remain trapped inside the city.
Those who have managed to escape have told harrowing tales of dodging sniper fire and mines or paying smugglers to lead them out.
Last month, the emergency coordinator for northern Syria for the group Doctors Without Borders (MSF), Puk Leenders, said the battle in Raqqa had created a humanitarian crisis.
"There is supply but it's very, very limited and the needs of the population are very high," Leenders said.