Photo: Reuters

Syrian rebel fighters have launched an assault on government-held districts of Aleppo, after troops cut their only route into the divided northern city, the BBC reports.

The rebel operation began at dawn on several fronts, with hundreds of shells being fired at western areas.

State media said eight people were killed and dozens hurt by the barrage.

The attack follows a failed attempt by rebels to re-open the Castello Road, the only way out of the rebel-held east for some 300,000 people living there.