An al-Qaida-affiliated organization posted an online video of the execution-style shooting of 18 Iraqi security troops kneeling on the ground near a citrus grove. The three-minute video, posted Saturday on a Web site previously used by the Islamic State of Iraq, claimed the 18 kidnapped government security forces were slain in retaliation for the alleged rape of a Sunni woman by members of the Shiite-dominated police. The video's authenticity could not be immediately verified. The tape firsts depicts the 18 men, some in Iraqi military uniforms, blindfolded, hands tied behind their backs and lined up in three rows before a screen. The men in the front row are kneeling. Armed masked men were seen pointing machine-guns at the captives. Male voices chant repeatedly in Arabic during the video: "At your service, sister" - a likely reference to the revenge for the allegedly raped Sunni woman. Another male voice is heard reading from the Islamic State of Iraq's statement posted on the same Web site Friday, saying the group's court has ordered the 18 security troops executed because Iraqi Prime Minister Nouri al-Maliki's government failed to meet the group's demands to hand over the officers who allegedly assaulted the Sunni woman in Baghdad last month, and to release all Sunni women detainees from Iraqi prisons. The voice also reads from a statement in Arabic that scrolls across the screen _ saying the group brings its leader, Sheikh Abu Omar al-Baghdadi, the "good news that your soldiers do not sleep." As soon as they "heard the call of the holy warrior" Abu Ayyub al-Masri - also known as Abu Hamza al-Muhajer, endorsed by Osama bin Laden as leader of al-Qaida's operations in Iraq in July 2006 - they "rose and attacked the dissenting security forces." Then the video moves to the scene of execution, with the men kneeling on the ground in a line, by a citrus grove, with date palm trees in the background. They are still blindfolded, hands tied in the back. Two masked militants, with checkered scarves on their heads, fire from handguns at close range into the backs of the men's heads, while a third militant carries a black banner ahead of them. As they are shot, the victims fall, head forward to the ground. The shooting is accompanied by chants of "Allahu Akbar," or "God is the Greatest." The al-Qaida linked group did not say when the 18 security troops were kidnapped in Diyala province. Earlier Saturday, the same group posted a text statement on the same Web site, saying that the 18 security troops were not the same as 14 Iraqi policemen whose bodies were found northeast of Baghdad on Friday. The group claimed it had seized on Thursday and killed the 14 policemen in a different operation from the capture of the 18 troops. The policemen were also slain in retaliation for the alleged rape of the same Sunni woman, it said. The statement's authenticity could not be independently confirmed. The "Islamic State of Iraq" was established in October by a coalition of Sunni Arab insurgent groups, chief among them al-Qaida in Iraq.