The body of an American hostage in Iraq, whose beheading was shown on a video on the Internet, has been recovered and identified, a US official said tonight.
"His body has been recovered and it's been identified," a US official reporters.
A militant group headed by al Qaeda ally Abu Musab al-Zarqawi earlier said it had beheaded an American hostage and posted a video of the killing on the Internet.
Mr Eugene Armstrong was kidnapped along with another American and a Briton.
The video, on an Islamist Web site, identified the hostage as Mr Eugene Armstrong and showed a masked man sawing his head off with a knife.
The video showed the banner of Zarqawi's Tawhid and Jihad group, which said it had kidnapped the hostage along with another American and a Briton and set a 48-hour deadline on Saturday to kill them.
In the video, five armed and masked men stood around the hostage, who was dressed in an orange overall typical of US jails and associated around the world with images of Muslims detained at Guantanamo Bay.
After reading a lengthy statement, during which the hostage sat rocking on the floor, one of the gunmen decapitated him.
Tawhid and Jihad, in a video posted on the Internet on Saturday, said it would slit the throats of Mr Armstrong, American Mr Jack Hensley and Briton Mr Kenneth Bigley - unless Iraqi women were freed from the Abu Ghraib and Umm Qasr prisons by today.
The US military says no women are being held in the two prisons specified, but that two are in US custody and are accused of working on ousted Iraqi President Saddam Hussein's weapons programme.
In addition to the British appeals, Mr Hensley's wife, Patty, appeared on Al-Jazeera television today, saying she believed her husband, like all Americans in Iraq, was there to help the Iraqi people.
On Al-Jazeera's main competitor, Al-Arabiya: British Foreign Office spokesman Mr Dean McLoughlin said in Arabic: "We strongly appeal for any information that could help us in releasing Kenneth. We promise complete confidentiality and not to make public the identity of whoever provides such information."
The comments of Mr McLoughlin, who spoke against a background picture of the Houses of Parliament, were broadcast repeatedly on Al-Arabiya today. He urged people with information on the hostages to call either the British Embassy in Baghdad or Iraqi police, and he read out the telephone numbers.
Mr Bigley's younger brother, Philip, also appeared on Al-Arabiya.
Mr Philip Bigley, who recorded at a studio in Liverpool, said his brother loved the Arab world and had worked in Qatar, Oman, Jordan and the United Arab Emirates.
"At the end of the day, we just want him home safe and well, especially for my mum, Lil," he added.
Zarqawi's Tawhid and Jihad group has claimed responsibility for most of the bloodiest suicide bomb attacks in Iraq since the fall of Saddam. It has already beheaded several hostages including US telecommunications engineer Nicholas Berg in May and South Korean driver Kim Sun-il in June.
The group released Filipino captive Angelo de la Cruz in July after Manila bowed to its demands to pull its troops out.
The United States has offered $25 million for information leading to the death or capture of Zarqawi, a Jordanian, and has launched a series of air strikes on his suspected hideouts in the rebellious town of Falluja, west of Baghdad.
Meanwhile an Islamist group has released 18 Iraqi soldiers it had captured and threatened to kill unless an aide to Shi'ite rebel cleric Moqtada al-Sadr was released, Arabic television Al Jazeera reported today.
The channel gave no further details.
Yesterday, Jazeera showed a video from the kidnappers, the Mohammad bin Abdullah Brigades, standing near a group of uniformed men apparently from Iraq's National Guard.
It said the captors were demanding the release of Sadr aide Hazem al-Araji, a Shi'ite cleric, within 48 hours or they would kill their hostages.
A senior aide to Sadr, Mr Ali Smeisim, held a news conference earlier on Monday to denounce the kidnapping of the guardsmen and call for their release.
The latest strike was this afternoon, residents said. Doctors said at least two people were killed.
In the northern city of Mosul, a car rigged with explosives blew up killing all three inside the vehicle in what was probably a premature detonation of the bomb, police said.