An Islamist website on Wednesday carried a videotape showing a "CIA agent" beheaded by militants in Iraq.

In the four-minute footage, a young Western-looking man is seated on a chair flanked by masked gunmen. One of the men uses a sword to cut through the man's neck and severed his head.

The footage was titled "Video of the beheading of an American CIA operative in Iraq."

The authenticity of the poor-quality video could not be immediately verified.