The fighting is a significant escalation since rebels launched a surprise offensive earlier this week, seizing towns and villages as they cut a path toward Syria’s second-largest city.

Insurgents breached Syria’s second-largest city Aleppo after blowing up two car bombs on Friday and were clashing with government forces on the city's western edge, according to a Syria war monitor and fighters.

Syrian opposition forces claim to have entered Aleppo city from the western side, according to a statement released on Friday by the newly formed rebel coalition, the Military Operations Command.