CAIRO, Egypt - An Islamic Web site carried a videotape appearing to show militants in Iraq beheading a man identified as a CIA agent. The authenticity of the videotape could not be verified immediately.
A U.S. official, speaking on condition of anonymity, said CIA officials have accounted for all employees and no one is missing. U.S. officials were working to determine if the tape was authentic, the official said Wednesday.
The Internet site, which Islamic extremists often use to post tapes and statements, on Wednesday displayed footage of eight militants surrounding a seated man.
A sign around the man's neck showed his photograph and carried a message saying he was a CIA agent and what appeared to be an official pass bearing the word "visitor" written in English. A brief statement posted Thursday on the same Web site by a previously unknown group, which purports to be a splinter of Jordanian militant Abu Musab al-Zarqawi's Tawhid and Jihad organization, claimed responsibility for killing the man.
The group, calling itself the Green Brigade, said it "arrested one of the American agents in Iraq and beheaded him as an example to others."
No details of the captive's identity were provided in the statement, the authenticity of which could not be immediately verified.
Comments on two Web sites that showed the footage raised suspicions that the beheaded man was an Egyptian accused of spying for the Americans.
One Islamic Web site carried the video with the headline: "Beheading an Egyptian agent of the CIA."
One commentator on another forum cited reports of the beheading of an Egyptian spy and asked if this was the same man.
The footage, titled "Video of the beheading of an American CIA operative in Iraq," lasted more than four minutes and included several scenes, including a masked militant holding a large knife to the captive's throat.
On the tape, a man was heard telling the captive in Arabic "put down your hand, this is the last time, next time I will gouge your eyes out." Then in English, he tells the captive, "open your eyes, open your eyes."
The footage was shot during the daylight hours in a house that appeared to be in a rural area. Date palm trees could be seen behind a mud brick wall. The location of the house was not given in the videotape.
The page on the Web site that carried the footage also included the word Al-Qaida, the militant group headed by Osama bin Laden and blamed for the Sept. 11 attacks on the United States. There was nothing else to linking Al-Qaida to the tape.
The eight militants shown on the tape were armed, one with a rocket-propelled grenade launcher, and wore traditional black or white Arab robes that are often seen in rural Iraq.
The captive, who appeared to be Caucasian and wore a brown T-shirt and light-colored pants, was shown seated on a chair in what appeared to be the courtyard of a house surrounded by eight masked militants.
In a subsequent shot, a masked man was shown standing alongside the captive holding a large saber-like sword. The masked man then chops repeatedly at the captive's neck, severing the head. The militant then held the head aloft and other voices repeatedly yelled "Allahu Akbar" - Arabic for "God is Great."
The tape did not identify the group shown in the footage. Jordanian militant Al-Zarqawi has claimed responsibility for previous beheadings in Iraq, including American businessman Nicholas Berg.
At least three Americans are known to be missing in Iraq - U.S. Army Spc. Keith M. Maupin and civilian contract workers William Bradley and Timothy Bell. The men have not been seen since an April 9 attack on a fuel convoy, although Arab television reported June 29 that Maupin had been killed. The U.S. military has said it could not confirm the death.
They are among at least 80 people taken hostage in Iraq in recent months -some for ransom and some by militants seeking to drive foreign soldiers from the country.
On Saturday, a video posted on a militant Web site that purportedly showed an American being decapitated in Iraq was a hoax. The man shown in the video said he videotaped the staged beheading at his friend's house using fake blood.