In this photo provided by the Mecklenburg County Sheriff's Office, Steven D. Green is shown in A booking mug shot at the Mecklenburg County jail in Charlotte, North Carolina, July 3, 2006. [AP]

Three US soldiers were charged with the rape and murder of an Iraqi teenager and killing her family, bringing to four the number of Americans accused of the four deaths in March, the US military said on Sunday.

A fourth soldier was charged on Saturday with dereliction of duty for failing to report the case.

Last week a fifth soldier, Steven Green, who has now left the army, was charged with rape and murder in a US civilian court over the killings at Mahmudiya, near Baghdad.

The case, one of several serious accusations against US troops in Iraq in recent weeks, has outraged many Iraqis and prompted some to call for American forces to leave.

Prime Minister Nuri al-Maliki called for a review of US troops' immunity from prosecution under Iraqi law.

In US federal court documents, prosecutors said Green went with three other soldiers from the checkpoint they were manning to a nearby house where Green killed two adults and their younger daughter before raping and killing the other girl.

A second soldier also took part in the rape, other soldiers involved alleged. The two other soldiers who went into the house told prosecutors they did not kill or rape anyone.

A fifth soldier in the unit said he was aware of the crime committed after the other four had been drinking and talking about rape but that he had not reported it afterwards.

"On July 8, 2006, the four soldiers were charged in connection with their alleged participation in the rape and murder of a young Iraqi woman and three members of her family," the 101st Airborne Division said in a statement.

"The fourth Soldier was charged with dereliction of duty for his failure to report the rape and murder of these Iraqi civilians, but is not alleged to have been a direct participant in the rape and killings.

"All are charged with conspiring with former Private First Class Steven D. Green to commit these crimes."

The soldiers face further investigation and a hearing to determine whether the evidence merits a court martial.

The military statement did not identify the four soldiers newly charged. Green was from the 502nd Infantry Regiment, a unit of the 101st Airborne Division.