A U.S. Marine sergeant accused of leading a 2005 massacre of 24 civilians in Haditha, Iraq, was spared jail time on Tuesday for his role in a case that brought international condemnation of American troops.

Staff Sergeant Frank Wuterich, 31, who pleaded guilty on Monday to one count of dereliction of duty, was sentenced to a demotion to the rank of private.

Earlier in the day, he expressed sorrow for the killings but insisted that no one in his combat unit behaved in any way that was dishonourable or contrary to the highest ideals of the Marine Corps.

Wuterich pleaded guilty as part of a deal with military prosecutors in which more serious charges of involuntary manslaughter and aggravated assault were dismissed.

The plea deal, decried by a victim's relative as an insult to all Iraqis, cut short Wuterich's court-martial and ended the final prosecution over killings that roiled the Marine Corps and drew international condemnation of American troops.

As part of his guilty plea, Wuterich accepted responsibility for providing negligent verbal instructions to the Marines under his command when he told them to shoot first and ask questions later, which resulted in the deaths of innocent civilians.

Wuterich, in his pre-sentencing statement, added that when he gave that order, the intent wasn't that they should shoot civilians. It was that they would not hesitate in the face of the enemy.

The squad leader, who was originally charged with murder in the case, said he realized that his name will always be associated with a massacre, being a cold-blooded baby killer, an 'out-of-control monster.'

But he insisted that he and his fellow Marines behaved honourably under extreme circumstances, and said he never fired my weapon at any women or children that day.

In a final plea for leniency, his civilian defense lawyer, Neal Puckett, said his client is not evil.

He is decent and moral, and his integrity is unfaltering, Puckett said. He knows that his Marine Corps career has come to an end.

FACES MAXIMUM THREE MONTH SENTENCE

Wuterich faced a maximum sentence of three months of confinement, forfeiture of two-thirds of his pay for three months and a reduction in rank, a Camp Pendleton spokesman said. Any discharge process faced by Wuterich, a father of three girls, will be separate from his sentencing.

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 was accused of being the ringleader in a series of November 19, 2005, shootings and grenade attacks that left two dozen civilians dead in Haditha, a city west of Baghdad that was then an insurgent hotspot.

The killings were portrayed by Iraqi witnesses and military prosecutors as a massacre of unarmed civilians -- men, women and children -- carried out by Marines in anger after a member of their unit was killed by a roadside bomb.

Defense lawyers argued the deaths resulted from a fast-moving combat situation in which the Marines believed they were under enemy fire.

In his statement on Tuesday, Wuterich, directed an apology to family members of those killed in Iraq, he said, Words cannot express my sorrow for the loss of your loved ones. But he insisted civilians were not singled out for attack.

The truth is, I don't believe anyone in my squad ... behaved in any way that was dishonourable or contrary to the highest ideals that we all live by as Marines, he said, reading calmly and deliberately. But even with the best intentions, sometimes combat actions can cause tragic results.

Called to the stand as a character witness on Tuesday, Jeffrey Dinsmore, an intelligence officer with Wuterich's battalion, said insurgent groups ... had complete control over the city (of Haditha) at the time and the unit had received word that an ambush was likely.

He also said insurgents were known to commandeer homes as places to launch attacks and to deliberately use civilians as human shields.

Six out of the eight Marines originally accused in the case had their charges dismissed by military judges, and a seventh was cleared of criminal wrongdoing.

Wuterich enlisted in the Marines after his 1998 graduation from high school, where he was an athletic honour-roll student and played with the marching band. He was serving his second tour of duty in Iraq when the Haditha incident occurred.

(Writing by Steve Gorman; Editing by Cynthia Johnston and Doina Chiacu)