An Iraqi Al Qaeda-led group on Sunday posted a video of the killing of three detained Iraqi officers, saying the government had ignored demands set for their release.
A militant wearing a black mask shot the men in the head with a pistol at the side of a road as cars passed by, an unusual setting as previous "executions" have been filmed in secluded areas.
The video, posted on a Web site used by insurgents in Iraq, showed the three men were blindfolded as they knelt by the roadside in their military uniforms. The trousers of two of them were lowered to the ankles.
Other militants chanted "God is great" during the killings.
The militants had demanded the release of a group of people it said were arrested in a mosque and a hospital in Baghdad.
"After there was no response to the conditions of the Islamic State, the sharia court in Mosul province decided that God's ruling should be carried out against Colonel Khaled Ahmad Hussein and his two companions," the group said in an on-screen statement.
Hussein was shown at gunpoint in the video saying: "I advise all of those working with the government of tyranny to return to their senses and work with the mujahideen and the Islamic State in Iraq."
The other two echoed his words. They identified themselves but their voices were inaudible.
On Thursday, the group showed the killing of nine abducted police and army officers, after an ultimatum it gave to the Iraqi government expired.
In March, the bodies of 14 Diyala-based policemen abducted by the group were found shot in the head.