i civilians, including a girl aged eight, were shot dead by British soldiers in southern Iraq.

"In a number of cases UK soldiers have opened fire and killed Iraqi civilians in circumstances where there was apparently no imminent threat of death or serious injury to themselves or others," the report says.

The fresh criticisms come at a time when the government is under mounting pressure to reveal how much was known about the abuses of prisoners at the American-run Abu Ghraib jail near Baghdad.

Separate cases involving the abuse of prisoners by British soldiers in jails in southern Iraq are being heard at the high court in London.

Amnesty said at the weekend that the abuse of Iraqi prisoners was a war crime, and said that as early as May last year it had warned the Ministry of Defence about the torture of Iraqi prisoners in British custody.

"The British army's response to suspected unlawful killing of civilians has undermined, rather than upheld, the rule of law," it says. "The investigations have been shrouded in secrecy."

For each new case identified by Amnesty there has either been no investigation by the military or the findings have been kept secret from the families of the dead.

In interviews with the Guardian yesterday two of the victims' families described incidents in which British soldiers shot dead civilians and then months later failed to produce any evidence of an investigation.

In the most damning case relatives described how Hanan Saleh Matrud, a girl aged eight, was shot dead by a British soldier outside her home in Qarmat Ali, near the southern city of Basra, on August 21 last year.

Two months later a letter from the British military admitted a soldier from B Company of the 1st Battalion of the King's Regiment had fired a "warning shot into the air" near the child's home that day.

The letter refused to apologise for the killing and said it was only "a possibility" that a British bullet had killed the child. Although privately officers apologised to the family and promised an investigation, the MoD has not publicly acknowledged taking any action in the case.

In a second incident Ghanem Kadhem Kati, an unarmed young man, was shot twice in the back by a British soldier at the door to his home on January 1. Troops had arrived at the scene after hearing shooting, which neighbours said came from a wedding party.

Investigators from the Royal Military Police exhumed the teenager's body six weeks later but have yet to offer compensation or announce any conclusion to the inquiry.

Other cases highlighted by Amnesty include a man who was shot dead during a demonstration in which stones were thrown at British military vehicles. Officers later offered his family $1,400. In another case two men were shot dead by British troops after bullets were fired into the air during a funeral.

Six of the civilian deaths highlighted in the report took place in August and September last year and involved soldiers from the 1st Battalion of the King's Regiment.

"More than a year after the occupation of Iraq, civilians are still being killed unlawfully every day by coalition forces, armed groups and individuals," Amnesty's report says.

The organisation says "dozens of, possibly hundreds of, civilians" have been killed by armed groups and individuals in southern Iraq since the war. In several cases former Ba'athists had been executed in apparent revenge attacks, and shopkeepers selling alcohol and music had been targeted. It said the British military and Iraqi police had failed to prevent, deter or investigate these killings.

The MoD admitted in February that British soldiers had killed 37 civilians in Iraq since May last year but that only 18 cases were being looked at by the special investigations branch of the Royal Military Police.

It complains that commanding officers, who were not impartial, made the decision whether or not to investigate killings.

"RMP investigations are shrouded in secrecy and lack the level of public scrutiny required by international standards," Amnesty says.

It calls on the British military to make public its highly secret "rules of engagement" for the Iraqi operation, which determine under what specific circumstances soldiers are allow to fire their weapons.

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