"At least 17 civilians were killed during the night in US-led coalition strikes on Raqa city and its suburbs," said Rami Abdel Rahman, head of the Britain-based Syrian Observatory for Human Rights monitor yesterday.
Tens of people were injured and the death toll could rise higher, he warned.
The monitor said there were at least 25 strikes, with most of the civilians killed as the planes hit an internet cafe in the western suburb of Jazra.