Separate air raids in northern Syria by regime aircraft and warplanes of the US-led international coalition killed at least 25 civilians on Friday, a monitoring group said.

President Bashar al-Assad's air force attacked a crowded market in Aleppo city's rebel-held district of Tariq al-Bab, killing 11 people, the Syrian Observatory for Human Rights reported.

Another five people were killed in an air raid on the southern rebel-held neighbourhood of Sheikh Said, it said.

The Britain-based monitor said rebel bombardment of government-held districts killed two civilians in the city that has been divided since July 2012. 

It also said a coalition raid on the northern city of Manbij, where US-backed fighters are battling the Islamic State jihadist group, killed two women and their seven children.

Kurdish and Syrian Arab fighters have been advancing on Manbij, an important waypoint between the Turkish border and Raqa, the jihadists' de facto capital.

The conflict in Syria has killed more than 280,000 people over the past five years and displaced millions from their homes.

Source: AFP