Syrian rebels have entered Aleppo for the first time since 2016 after launching a surprise offensive earlier this week. The insurgents, led by Hayat Tahrir al-Sham, have clashed with government forces on the city's western edge. The offensive comes as Iran-linked groups, including Hezbollah, have been preoccupied with their own battles. The aim of the offensive is to reestablish the boundaries of the de-escalation zone. The fighting has displaced thousands of families and disrupted services in the area.