At face value, Sunni extremist groups target Shiites because of a historic conflict between the two branches of Islam. Theological disagreements between Shiite and Sunni Muslims date back to 680 A.D., when the former refused to acknowledge the legitimacy of the new caliphate, or leadership. The refusal and the subsequent response from pro-Caliphate Sunnis sparked a historic battle – the Battle of Karbala – where the grandson of the prophet Muhammad, Husayn, was killed. Shiites mourn the martyrdom of Husayn to this day.
However, though the historical and theological differences between the two groups surface in explanations provided by Sunni militants, analysts and activists in Pakistan surmise that Saudi Arabia and Iran are carrying out a proxy war on Pakistani soil by providing financial and other support to militants from both camps. For example, the banned Shiite militant group, Sipah-e-Muhammad Pakistan, was formed with the explicit purpose of targeting leaders in SSP and LeJ in response to increased attacks against Shiites.
