The Islamic State of Iraq posted a video on the Internet showing a militant shooting the blindfolded men in the head in an open field. Their hands were tied behind their backs.
The authenticity of the tape, which was posted on a website used by Iraqi insurgents, could not be verified.
In an earlier video posted on the website, the group had threatened to kill the men if the "Bush-aligned government" failed to meet its demands within 72 hours. The demands included releasing Sunni women detained in Interior Ministry prisons, and handing over those responsible for the alleged rape of a Sunni woman while she was detained by Interior Ministry officers.
The Islamic State of Iraq issued similar demands when it captured nine Iraqi security personnel last month. It later followed through on its threat and killed the nine hostages.