Fighter jets have bombed eastern areas of Syria's second city Aleppo, BBC News reported.

The attack is seen as a significant escalation in the conflict.

It is thought to be the first time that warplanes have been used in Aleppo, BBC News said.

Rebels launched an offensive against Aleppo at the weekend in an attempt to wrest control of the city from the army. Fierce fighting has been reported close to Aleppo's old city.