Six employees of Kentucky Fried Chicken, the American fast food chain, were killed in Karachi overnight Monday when their restaurant was set on fire by Shia youths seeking revenge for a suicide bomb attack on a local mosque, police and rescue workers said.

The KFC outlet, located in the southern city’s densely populated Gulshan-e-Iqbal district, was ransacked in a riot that also damaged petrol stations, bank branches, shops and dozens of vehicles.