The video showed five men wearing headscarves and black ski masks, standing over a bound man in an orange jumpsuit - similar to a prisoner's uniform - who identified himself as Nick Berg, a U.S. contractor whose body was found near a highway overpass in Baghdad on Saturday.
"My name is Nick Berg, my father's name is Michael, my mother's name is Susan," the man said on the video. "I have a brother and sister, David and Sarah. I live in . . . Philadelphia."
After reading a statement, the men were seen pulling the man to his side and putting a large knife to his neck. A scream sounded as the men cut his head off, shouting "Allahu Akbar!" - "God is great!" They then held the head out before the camera.
"For the mothers and wives of American soldiers, we tell you that we offered the U.S. administration to exchange this hostage with some of the detainees in Abu Ghraib and they refused," one of the men read from a statement.
"So we tell you that the dignity of the Muslim men and women in Abu Ghraib and others is not redeemed except by blood and souls. You will not receive anything from us but coffins after coffins . . . slaughtered in this way."
The video bore the title "Abu Musab al-Zarqawi shown slaughtering an American." It was unclear whether al-Zarqawi - a lieutenant of Osama bin Laden - was shown in the video, or was claiming responsibility for ordering the execution.
The website on which the video was posted is known as a clearing house for al-Qaida and Islamic extremist groups' statements and tapes.
You will not receive anything from us but coffins after coffins . . . slaughtered in this way.
Way to strengthen the will of the American people to finish this job.
This jackass won’t see December.
This is why we must never prevent the so-called "Muslim call to prayer" from being broadcast over loudspeakers in American towns.
"ALLAHU AKBAR!" = "HEIL HITLER!"
MEIN KORAN = MEIN KAMPF