They are forced to leave them in piles in the overloaded freezer compartments or send them for burial in anonymous graves.

Last month there were 972 corpses received, almost all victims of violent death. The vast majority were brought in with bullet holes. Many had their hands bound and faces mutilated.

No one knows quite how many people are being killed in Iraq or by whom.

But the evidence at Baghdad's mortuary shows that the number has increased and that the number of Iraqis killed in the capital every two months is equivalent to the total number of US troops to die in the conflict so far.

Since July, the number of bodies counted at the mortuary has hovered around 1,000, up from 596 in March. Three quarters are male, most aged between 15 and 45.

"We have to cope with extraordinary numbers," said Faed Bakr, the facility's director.

May saw a record number of bodies from suicide bombings, June beheadings and now it is assassinations and drive-by shootings.

Under medical law any person who dies from natural causes can have their death certificate issued by a doctor.

Only those who die violently or suspiciously have to be sent to a mortuary. Some are the result of road crashes, others are household accidents.

Most are the victims of what started as an insurgent resistance to foreign "invaders" and is now evolving into a sectarian struggle between Shia Arabs and Sunnis.

Post mortem examinations reveal that a significant number of gunshot deaths involve a single bullet, execution style.

There are cases of people having had electrical drills forced through their skulls and into their brains. Others have had their eyes burnt out. Many had hands bound by tape or handcuffs.

The mortuary echoes with the cries of anguish and anger from relatives. One young man being held up by two friends at the entrance, shouted at the sky demanding how he could be living in a world where his four brothers were snatched from their family home by a gang of masked gunmen.

Inside the faded yellow brick building, groups huddled around computer terminals as attendants displayed pictures of the bodies yet to be identified, their faces white and expressionless and photographed lying on a mortuary slab.

One woman, Um Hussein, recognised her son - only to be told that overcrowding meant his body had already been taken to Najaf for burial at the cemetery there.

Her remaining three sons were given the plot number so they that could make the journey to dig up the corpse to transfer him to the family's burial plot in the suburbs of Baghdad.

"We are trying to expand our facilities so we can have more storage," Mr Bakr said. "But there is no money for new buildings or extra staff. We have only 12 pathologists. It is very difficult."

Though it is the suicide bombings with their mass casualties that gain the most attention it is these individual cases of shootings that are now the primary cause of loss of life in this conflict.