About 151,000 Iraqi civilians were killed in bomb attacks and other violence in Iraq in the first three years after the invasion, according to the most comprehensive study yet into the number of fatalities.

The World Health Organisation (WHO) based its estimate on a survey of nearly 10,000 households, conducted jointly with the Iraqi Government. It said that the actual figure of violent deaths between March 2003 and June 2006 could be as high as 223,000 or as low as 104,000.

Many more people have died over the past 18 months, leaving the overall civilian death toll of the war to date unknown.

Salih Mahdi Motlab al-Hasnawi, the Iraqi Health Minister, expressed confidence in the findings of the United Nations’ health agency. "This is a very sound survey,” he said, noting that the research demonstrated “a massive death toll since the beginning of the conflict”.

Iraq timeline: five years of conflict

From accusations that the weapons of mass destruction dossier had been sexed-up to withdrawal of British troops from Basra

Multimedia

• Poll: Was Iraq war worth the sacrifice?

• Audio slideshow: Iraq conflict explained

• Pictures: Iraq, war and aftermath

Related Internet Links

• Read the Inside Iraq blog from our team in Baghdad

Related Links

• Suicide bomber wrecks Iraqi army celebration

• I felt a new terror on Basra's streets

• Iraq surge brings hope for a day without death

Multimedia

• Pictures: Life in Iraq

The WHO estimate is much lower than a disputed tally of more than 600,000 published in the medical journal The Lancet in 2006, but it is nearly double the figure given by the human rights group Iraq Body Count, which makes its calculations from media reports and hospital and morgue records.

Counting civilian casualties in a warzone is an imprecise science, with many deaths going unreported because of the danger and disorder. In Iraq in particular the death toll from an attack is sometimes inflated or reduced because of sectarian bias. Also, according to Muslim burial traditions, a victim's family may bury the body one on the day of death reporting the incident.

The WHO study, which also questioned families on other topics such as pregnancy and disease, found that since the war began violence was the main cause of death for men aged 15 to 59.

On average, 128 Iraqis a day died of violent causes, such as shootings, roadside bombs and suicide attacks, in the first year after the US-led invasion. The average daily tally eased to 115 in the second year and rose to 126 in the third year. More than half of the violent deaths occured in Baghdad.

Sanaa al-Soudani’s world was turned upside down on the morning of May 14, 2004 when a car bomb outside the Iranian Embassy in Baghdad killed her husband, Jabber Hussain, as he was travelling to work.

“I cry every night when I remember him,” said Ms al-Soudani, 31, who must bring up their three, young children alone. “Why did they kill my husband, what he did to them? Why did they destroy my happy life?”

Sectarian bloodletting escalated across Iraq after an attack on a revered Shia shrine in the central city of Samarra in February 2006. The killings started to subside only last summer after a "surge" of 30,000 extra US troops in and around Baghdad, coupled with a ceasefire by the Mahdi Army loyal to Hojatoleslam Moqtada al-Sadr, the powerful Shia cleric, and a decision by some Sunni insurgents to side with the US military.

Emaad Salem al-Hilli, 21, lost his entire family in the chaos — deaths that were not included in the WHO’s survey because they ccurred only last February. Gunmen in three vehicles drove up to his house in Zayouna, a largely Sunni neighbourhood close to the centre of Baghdad, and shot his mother and father dead before kidnapping his 16-year-old brother, who has not been seen since.

The reason – his father, a Shia Arab, prayed at a Sunni mosque.

“This incident destroyed my life,” said Mr Hilli, who escaped only because he had been up on the roof of the house, feeding the family dog. He has since fled to Jordan, where he is a student.

The US Department of Defence, for its part, said that enormous precautions were taken to avoid civilian deaths and injuries. The White House, which said it had not seen the WHO study, expressed sorrow at any deaths in Iraq. “The unmistakable fact is that the vast majority of these deaths are caused by the willful, murderous intentions of extremists committed to taking innocent life,” said Tony Fratto, the White House deputy press spokesman .

Almost 1,000 neighbourhoods and villages were visited across Iraq’s 18 provinces to collect the data for the report, but safety concerns prevented statisticians from visiting some areas, including parts of Baghdad and Ambar province to the west. Instead, estimates were made using a formula based on information gathered by Iraqi Body Count.

One statistician was killed during the project and another shortly afterwards. The research was conducted by Iraqi Ministry of Health employees during late 2006 and early 2007.

On the military side, 174 British and about 3,915 American troops have died since the invasion was launched. Between 4,900 and 6,375 members of the Iraqi security forces are also thought to have perished, however there are no official figures available.

Times Recommends

• Violent video games won’t corrupt
• Pope Benedict XVI: Alma Mater
• Chávez should know what’s good for him