Seven US marines and a navy corpsman have been charged with murder, conspiracy, assault, kidnapping and obstruction of justice, among other charges, over the death of an Iraqi in Hamdania, a village west of Baghdad.
The marines allegedly took a 52-year-old disabled man, Hashim Ibrahim Awad, from his house, shot him and then left a shovel by his body to make it appear that he had been planting a roadside bomb.
"The Marine Corps takes allegations of wrongdoing by its members very seriously and is committed to thoroughly investigating such allegations. The Marine Corps also prides itself on holding its members accountable for its actions," Marine Colonel Stewart Navarre said in Camp Pendleton, California, on Wednesday.
He added that he could not discuss the specifics of the case and said it "is critical to remember that the accused are presumed innocent".
Defence lawyers have suggested that investigators got incriminating statements by using inappropriate interrogation methods.
All eight men face the possibility of the death penalty if convicted.
Navorre (C) said the marines will
be held accountable
In a separate case, the military said a fourth soldier had been charged with premeditated murder in connection with the shooting of three detainees in Iraq on May 9.
On Monday, the US military said three other soldiers had been charged with the killings and with threatening to kill a fellow soldier if he told authorities the truth about the case.
These cases are the latest involving allegations of US soldiers killing Iraqi civilians.
The Naval Criminal Investigative Service has been investigating allegations that marines killed 24 Iraqi civilians on November 19 at the town of Haditha.
Separately, a US Army official in Washington said on Wednesday that Iraqi soldiers, not anti-government fighters, killed two US military trainers in 2004, adding that a months-long investigation found the original story of an ambush was false.
US soldiers frequently conduct
joint patrols with Iraqi forces
One Iraqi trainee has been detained and is awaiting prosecution for the shooting of 1st Lieutenant Andre Tyson and Sergeant Patrick McCaffrey, both members of the California Army National Guard, the official said.
The US soldiers were conducting a joint patrol during initial training operations with Iraqi forces on June 22, 2004, the official said.
Initially, the army said the US soldiers were killed by enemy fire in the city of Balad, located some 80km north of Baghdad, but a criminal probe found members of the Iraqi Civil Defence Corps were involved.
The investigation closed in September, but the US soldiers' families were not notified until this week, the army official said.
Findings from the investigation emerged as US servicemen were being detained in three separate cases involving the killing of Iraqis.