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.

The attack on Aleppo came after weeks of simmering low-level violence, including government attacks on opposition-held areas. Turkey, which has backed Syrian opposition groups, failed in its diplomatic efforts to prevent the government attacks, which were ...

Syrian rebels have entered the country’s second city of Aleppo, after launching a dramatic surprise attack on the government-held areas of northern Aleppo province earlier this week. The development is significant: not only was Aleppo previously seen as very well defended,