Strikes by a U.S.-led coalition against ISIS killed at least 15 civilians, including three children, in northeastern Syria on Thursday, activists said.
The strikes hit four ISIS-controlled villages in Hassakeh province, the Syrian Observatory for Human Rights said, saying the toll could rise.
It said nine ISIS fighters had also been killed in the strikes on the four villages.
The Britain-based monitor said the latest civilian casualties came after two days of civilian deaths in U.S.-led strikes in Hassakeh.