Scores of civilians killed in airstrikes on Raqqa

Overnight airstrikes on the Islamic State group's de facto Syrian capital, Raqqa, killed 25 civilians, a monitoring group said on Wednesday.

Of those killed, six were children.

"Dozens more were wounded, some of them critically," said the Syrian Observatory for Human Rights said. Activists were not immediately able to determine who carried out the Tuesday night raids.

The airstrikes came after IS dealt a significant blow to Russian-backed Syrian government forces, driving them out of Raqqa province after they came within just 20km (12 miles) of the Euphrates River and the country's largest dam.

Damascus lost more than 40 troops and militia in the militant counter-attack on Sunday and Monday, the UK-based Observatory said.