Staff Sergeant Frank Wuterich demoted to rank of private but will not go behind bars, a military spokesman said.
A US marine accused over the killing of 24 Iraqi civilians in the city of Haditha was demoted to the rank of private but will serve no time behind bars, a military spokesman has said.
Staff Sergeant Frank Wuterich, the last squad member to face justice after all the others were cleared, was sentenced to 90 days confinement but he will not serve it for procedural reasons, the spokesman said.
The sentencing hearing was held on Tuesday at Camp Pendleton, south of Los Angeles.
Word of the maximum sentence sparked outrage in Iraq, where Ali Badr, a Haditha resident and relative of one of the victims, called it "an insult to all Iraqis" and "solid proof that the Americans don't respect human rights".
Wuterich, 31, the commander of a unit whose other members have been exonerated, pleaded guilty on Monday to negligence, ending the final prosecution stemming from the 2005 incident.
He entered his plea as part of a deal with military prosecutors in which more serious charges of involuntary manslaughter and aggravated assault were dismissed.
Wuterich was initially charged with murder.
"Staff Sergeant Wuterich accepted responsibility ... and agreed and admits that he gave a verbal order to shoot first, ask questions later, or don't hesitate to shoot, and words to that effect," said spokesman Joe Koppel.
"That verbal instruction caused his marines to [not] positively identify targets in the two homes. And now, at the sentencing phase, he'll be held accountable for those actions."
The victims included 10 women and children killed at point-blank range. Six people were killed in one house, most shot in the head, including women and children huddled in a bedroom.
The other seven soldiers charged in the case had been exonerated through various legal rulings, fuelling anger in Iraq, where authorities had pushed for US troops to be subject to Iraqi justice before the US pullout in December.
Lawyers for the troops involved argued the deaths resulted from a fast-moving situation in which they believed they were under enemy fire.
"No one denies that the consequences of November 19, 2005 were tragic, least of all Staff Sergeant Frank Wuterich," his civilian defence attorney, Neal Puckett, said in a statement released shortly after the plea hearing.