Images shown on NBC news on Saturday has caused Marine commanders in Iraq to begin investigating an incident in which a Marine apparently shot and killed a severely wounded and unarmed Iraqi in a mosque in Fallujah, said a Pentagon official on Monday.

The tape displays a squad of Marines entering the building and seeing several Iraqis laying against a wall. It is unclear whether the soldiers are dead or severely wounded. One Marine shouts something about one Iraqi feigning death and the Marine shoots the man in the head.

The networks did not air the entire videotape, saying some of it was too graphic.

“NBC has chosen not to air the most gruesome of the images,” NBC anchorman Brian Williams said in the broadcast segment introducing the videotape.

The wounded men were insurgents who had battled a different group of Marines the day before. In that firefight, 10 Iraqi fighters were killed and five were wounded, according to Sites. Those five were treated with field bandages and left in the mosque because the conditions of combat and did not allow the Marines to bring them out. Sites also said other Marines were supposed to collect the wounded Iraqis and take them for treatment, but, for some reasons not yet known that did not happen.

Then, on Saturday, the Marines received a report that the area, which they thought had been cleared, had been reoccupied by insurgents, Sites said. A different squad of Marines that had not been involved in the previous day’s encounter was sent to investigate. It entered the mosque and saw the men lying on the floor. It was then that the shooting occurred, according to the videotape.

The Marine who shot the wounded Iraqi had been wounded the day before but returned to duty.Sho

The investigation began yesterday by the staff of the First Marine Expeditionary Force, of which the major ground unit is the First Marine Division. Sites was embedded with the Third Battalion of the First Regiment of the First Marine Division.

“My understanding is that the Marines have launched an inquiry into it. I wouldn’t jump to any conclusions. We don’t know all the facts here,” said Pentagon spokesman Bryan Whitman.

Lt. Gen. John F. Settler, commander of the First Marine Expeditionary

Force, in Fallujah, confirmed that an investigation was under way and added, “Let me make it perfectly clear: We follow the law of armed conflict. We hold ourselves to a high standard of accountability.”