A US army officer has recommended that four American troops face the death penalty if convicted of killing three detainees during a raid in Iraq.
US soldiers have faced several inquiries into their conduct
Investigator Lt Col James Daniel made the recommendation in a report, after finding "aggravating circumstances".
Army Staff Sgt Raymond Girouard, Spc William Hunsaker, Pfc Corey Claggett and Spc Juston Graber have admitted the killings in Tikrit in May.
They say they acted in self-defence, after the detainees tried to escape.
Under military law, the maximum penalty for premeditated murder is a death sentence.
The last execution of a US soldier took place in 1961, at Fort Leavenworth in Kansas.
The detainees died during a US military operation near the Thar Thar Canal near Tikrit in northern Iraq on 9 May.
The division was at the time involved in operation "Iron Triangle", targeting insurgents active in Salahuddin province and detaining hundreds of people.
Their unit commander ordered an inquiry on the day the alleged murders took place, apparently after soldiers became suspicious about the circumstances in which the detainees had died.
A criminal investigation began on 17 May, the US military said.
According to the charge sheet, Army Staff Sgt Girouard, Spc Hunsaker and Pfc Claggett are also alleged to have separately told another soldier that they would kill him if he testified against them.
US troops in Iraq have faced several accusations of unlawfully killing civilians and abusing detainees, prompting inquiries into their conduct.
The US military has been investigating the deaths of 24 unarmed civilians in the town of Haditha last year in an attack blamed on US marines.