BAGHDAD (AP) - Execution-style killings, not headline-grabbing bombings, have been the leading cause of death among civilians in the Iraq war, a study released Wednesday shows.
The findings, published in the New England Journal of Medicine, point to the brutal sectarian nature of the conflict, where death squads once roamed the streets hunting down members of the rival Muslim sect.
Estimates of the number of civilians killed in Iraq vary widely. The study was based on the database maintained by Iraq Body Count, a private group that among other sources uses media reports including those of The Associated Press.
The authors concede the data is not comprehensive but maintain that the study provides a reliable gauge of how Iraqis have died in the six-year conflict.
The findings also provide further evidence of the brutal sectarian cleansing and retaliatory violence between Shiites and Sunnis that pushed the country to the brink of civil war before easing a year and a half ago.
"I think that a lot of the executions with torture had to do with trying to get people to move out of their houses," said Michael Spagat, one of the study's authors. "It had to strike fear into people's hearts. A lot of it is just hatred and retribution."
The study covered the period from the March 20, 2003 invasion through March 19, 2008, in which 91,358 violent deaths were recorded by Iraq Body Count.
The total number of civilian deaths in Iraq is widely disputed, but the count by the London-based group is widely considered a credible minimum.
Apart from media reports, Iraq Body Count uses figures from morgues and hospitals since the war started.
However, the authors focused on only 60,481 deaths linked to specific events, excluding Iraqis killed in prolonged episodes of violence during the U.S.-led invasion and the U.S. sieges of the former insurgent stronghold of Fallujah in 2004.
The study found that 19,706 of the victims, or 33 percent, were abducted and killed execution-style, with nearly a third of those showing signs of torture such as bruises, drill holes or burns.
That compared with 16,922, or 27 percent, who died in bombings, most of them in suicide attacks.
The figures were similar to those recorded by the AP.
While the study didn't assign blame for the killings, death squads largely run by Shiite militias were believed to be behind many of the bullet-riddled bodies that turned up by the dozens on the streets of Baghdad and other cities - often stripped of any identification.
Those death squads were seeking revenge for the deaths of Shiite civilians at the hands of al-Qaida and other Sunni religious extremists in suicide bombings and other attacks.
The authors said the number of execution-style killings is likely to be higher because it excluded Iraq Body Count's morgue figures. The morgue numbers were omitted because the specific weapon used could not be determined in those cases.
Nor did they attempt to speculate how many missing people could be dead.
Although such killings continue, the numbers of bodies found every day have dropped to the single digits since the U.S. troop surge and a cease-fire called by the main militia leader, Shiite cleric Muqtada al-Sadr, in August 2007.
The drop in violence is also due in part to the fact that many formerly mixed neighborhoods in Baghdad have been effectively segregated after the minority sect was purged by the death squads. Baghdad has since become a maze of concrete walls and checkpoints aimed at ensuring security.
Marc Garlasco, a senior military analyst with the New York-based Human Rights Watch, blamed the sectarian violence and insurgency that followed the ouster of Saddam Hussein on poor postwar planning by the United States.
"It bears out what we have known for some time now - that there was a massive shift in the 2004 time frame from civilian casualties caused by U.S. and multinational forces to the insurgency," he said.
Only 4 percent of the Iraqi deaths included in the study, or 2,363, were a result of U.S. airstrikes, which frequently targeted suspected insurgents hiding in houses. But 46 percent of the victims whose gender could be determined were female and 39 percent were children.
The authors caution that those percentages may be inflated "because the media may tend to specifically identify female and young victims more readily than male adults among the dead."
The airstrikes also caused the largest number of civilian deaths in individual attacks, with an average number of 17 people killed in bombs dropped by warplanes, compared with an average of 16 people killed by suicide attackers on foot, the figures showed.
Garlasco, who was not involved in the study, said that reflected a grim reality.
"The airstrike data is very similar to Afghanistan in that when civilians are killed in an airstrike it tends to be a significant number," he said. "Air power can be a very discriminating force, but when mistakes are made civilians pay and they pay big."
The AP News Research Center in New York contributed to this report.
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