From The Economist:
All through 2012, Shias, who make up an estimated 30m of Pakistan’s 180m people, have been attacked in Karachi and across Pakistan, with shootings and bombings by extremist groups, many of whom have historic links to Pakistan’s security services. Before the blasts, death squads in Karachi and the western city of Quetta tracked down and shot doctors, lawyers and other professionals, the educated elite of the Shia community. As far afield as the normally serene mountainous region of Gilgit in the north-east, passengers have been pulled off buses, identified as Shias and then shot. In Karachi Shia militants have hit back on a small scale, killing some Sunni activists, but otherwise the slaughter is one-sided. According to Hasan Murtaza, an independent researcher, 456 Shia have been killed in targeted attacks this year, more than double the casualties of 2011.
The violence has been notable not just for its scale, but for what lies beneath it: a growing alliance between established anti-Shia militant groups and the Pakistani Taliban, Sunni extremists who have spun out of the army’s control, allied with al-Qaeda, and are determined to attack the Pakistani state.