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

It was the first time the city had been attacked by opposition forces since 2016, when they were ousted from Aleppo’s eastern neighborhoods following a grueling military campaign in which Syrian government forces were backed by Russia, Iran, and its allied groups.