BAGHDAD, Iraq (CNN) -- Six Iraqis were killed Saturday when a U.S. helicopter fired on a small gathering at what may have been a pro-U.S. group's checkpoint, officials said.
Men who said they were with an Awakening Council stand over the bodies of comrades killed Saturday in Iraq.

A Samarra police official said the helicopter "mistakenly" hit a Sons of Iraq checkpoint, killing the six. Two other Iraqis were wounded in the attack in Ashaki, south of Samarra, 55 miles north of Baghdad.
The U.S. military said that after five people were "spotted conducting suspicious terrorist activity" near a recent roadside bombing site, an AH-64 Apache fired on them. It was unclear how the other dead and wounded were involved.
The Sons of Iraq are one of many groups generically referred to as Awakening Councils -- largely Sunni local security groups that have been recruited by the U.S. military.
A U.S. patrol stopped and talked with the Sunni militiamen about two hours before the attack, a local Awakening Council leader told The Associated Press.
"They asked us general questions like: 'Have you gotten your IDs?' and 'Do you need anything?' and then they left," Sabbar al-Bazi told AP. "Two hours later, after I had gone home, I heard two explosions, probably caused by two missiles, and machine-gun fire from a helicopter."
The U.S. and Iraqi militaries are conducting a joint investigation, a U.S. spokesman said.