A video was posted on an Islamic Web site Monday showing purported Iraqi militants shooting dead two Iraqi policemen.
The Ansar al-Sunnah Army said it carried out the executions, but the claim could not be immediately verified.
The victims were shown wearing their uniforms and sitting on the ground in an open area, one with his hands tied behind his back and the other with his hands free. Both were then shot by someone standing off-camera using an automatic weapon.
After the execution, the camera panned to a sign reading in Arabic: "God's verdict has been implemented against the agents of the Crusaders."
In earlier scenes, the victims were shown sitting blindfolded and leaning against a wall. The men identified themselves as Haider Kareem Jassim and Ahmed Khammas, who were both from Baghdad and worked as policemen with the oil installations protection unit.
Both said they were captured while traveling from Baghdad to the northern city of Kirkuk. The group issued a statement saying the two were captured after a one-hour battle that allegedly killed 10 other policemen.
Monday's video was the second released by the group in the past five days after a tape posted Oct. 5 showed the beheading of two Iraqis that Ansar al-Sunnah alleged worked as spies for the U.S. forces.
Ansar al-Sunnah has previously claimed responsibility for a number of car bombings and attacks on U.S troops, foreign civilians and Iraqis that the group termed American "collaborators.", AP reported.
Following the summit in Riga on November 30, NATO Secretary General Jens Stoltenberg explained how the alliance could respond to Russia's 'new aggression against Ukraine.'