Forces loyal to President Bashar al-Assad are massing to launch an all-out assault on rebel-held areas of Aleppo, Syria's commercial hub. US State Department officials are warning of an impending "massacre", as you can read in this report by the New York Times.
In the past, alleged massacres committed by government troops have been blamed on the so-called "shabiha" militias, paramilitary forces staffed primarily with government loyalists from Assad's Alawite minority. Shabiha have acquired a fearsome reputation due to their blind allegiance to the regime and ruthlessness in carrying out the dirty work for the government troops. And now, they might be slipping out of regime's control.
Their history is no less violent. The term shabiha means "ghost" in Arabic and originates in the shadowy crime syndicates that emerged in the coastal city of Latakia in the 1970s.
Read more on the Shabiha militias. Can they win the war for Assad?