Syrian rebels have launched a lightning offensive on the city of Aleppo and surrounding regions, expanding their territory in northwest Syria. The rebels, led by Hayat Tahrir al-Sham (HTS), a former Al Qaeda affiliate, have united under a single leadership for the first time. HTS began as the Al Nusra Front, an extremist group that pledged allegiance to Al Qaeda in 2013. However, it rebranded in 2016, cutting ties with Al Qaeda and focusing on governing the territory it controlled. The group's rule has been less brutal than that of the Islamic State, but it remains unpopular among residents.