At least 15 civilians, including four children, were killed in a suspected US-led coalition airstrike today near the Islamic State group's Syrian bastion Raqa.'<br/><br/>The Syrian Observatory for Human Rights said at least 17 people were injured in the strike on Heneyda. The Britain-based group said, the death toll could rise further because several of the injured were in serious conditions.<br/><br/>Heneyda is around 25 kilometres west of the city of Raqa, the target of a major operation led by a Kurdish-Arab alliance of fighters and backed by the US-led coalition.