Carnage

BALTIMORE, Maryland (CNN) -- War has wiped out about 655,000 Iraqis or more than 500 people a day since the U.S.-led invasion, a new study reports.

Violence including gunfire and bombs caused the majority of deaths but thousands of people died from worsening health and environmental conditions directly related to the conflict that began in 2003, U.S. and Iraqi public health researchers said.

"Since March 2003, an additional 2.5 percent of Iraq's population have died above what would have occurred without conflict," according to the survey of Iraqi households, titled "The Human Cost of the War in Iraq."

The survey, being published online by British medical journal The Lancet, gives a far higher number of deaths in Iraq than other organizations.

Researchers randomly selected 1,849 households across Iraq and asked questions about births and deaths and migration for the study led by Gilbert Burnham of Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland.

They extrapolated the figures to reflect the national picture, saying Iraq's death rate had more than doubled since the invasion.

Iraqis "bear the consequence of warfare," the report said, comparing the situation with other wars: "In the Vietnam War, 3 million civilians died; in the Congo, armed conflict has been responsible for 3.8 million deaths; in East Timor, an estimated 200,000 out of a population of 800,000 died in conflict.

"Recent estimates are that 200,000 have died in Darfur [Sudan] over the past 31 months. Our data, which estimate that 654,965 or 2.5 percent of the Iraqi population has died in this, the largest major international conflict of the 21st century, should be of grave concern to everyone."

The researchers estimated that an additional 654,965 people have died in Iraq since the invasion above what would have been expected from the pre-war mortality rate.