September 2009 that overall attacks had decreased 85% in the last two years from 4064 in August 2007 to 594 in August. 2009: with 563 attacks in September (through September 28). (Patterns In Civilian Casualties in Iraq: 2004-2009) Bomb and mortar attacks Bomb attacks aimed at civilians usually targeted crowded places such as marketplaces and mosques in Shi'a cities and districts. The bombings, which were sometimes co-ordinated, often inflicted extreme casualties. For example, the 23 November 2006 Sadr City bombings killed at least 215 people and injured hundreds more in the Sadr City district of Baghdad, sparking reprisal attacks, and the 3 February 2007 Baghdad market bombing killed at least 135 and injured more than 300. The co-ordinated 2 March 2004 Iraq Ashura bombings (including car bombs, suicide bombers and mortar, grenade and rocket attacks) killed at least 178 people and injured at least 500. Suicide bombings Since August 2003, suicide car bombs were increasingly used as weapons by Sunni militants, primarily al-Qaeda extremists. The car bombs, known in the military as vehicle-borne improvised explosive devices (VBIEDs), emerged as one of the militants' most effective weapons, directed not only against civilian targets but also against Iraqi police stations and recruiting centers. These vehicle IEDs were often driven by the extremists from foreign Muslim countries with a history of militancy, such as Saudi Arabia, Algeria, Egypt, and Pakistan. Multiple suicide bombings had roughly the same target distribution as single blasts: about three-quarters of single and multiple blasts were sent against Iraqi targets. Death squads Death squad-style killings in Iraq took place in a variety of ways. Kidnapping, followed by often extreme torture (such as drilling holes in people's feet with drills) and execution-style killings, sometimes public (in some cases, beheadings), emerged as another tactic. In some cases, tapes of the execution were distributed for propaganda purposes. The bodies were usually dumped on a roadside or in other places, several at a time. There were also several relatively large-scale massacres, like the Hay al Jihad massacre in which some 40 Sunnis were killed in a response to the car bombing which killed a dozen Shi'a. The death squads were often disgruntled Shi'a, including members of the security forces, who killed Sunnis to avenge the consequences of the insurgency against the Shi'a-dominated government. Allegations of the existence of the death squads, made up of Shiites, and their role in executions of Sunnis, began