No negotiation and no retreat, vows Bush

When it came, the statement broadcast by the al-Jazeera Arabic news channel from Qatar was as chilling as it was ghoulish: A second American captive, Jack Hensley, 48, had been beheaded in Iraq after the lapse of a 24-hour deadline.

When it came, the statement broadcast by the al-Jazeera Arabic news channel from Qatar was as chilling as it was ghoulish: A second American captive, Jack Hensley, 48, had been beheaded in Iraq after the lapse of a 24-hour deadline.

Once again news of this videotaped murder came from the internet, posted by Abu Musab al-Zarqawi's Tawhid and Jihad group. The message gave few details, but promised that images of the "slaying" would soon be made available.

Mr Hensley's reported death came a day after the group beheaded the American engineer Eugene Armstrong, who was kidnapped along with Mr Hensley and the British hostage Kenneth Bigley.

Reaction to the killing was muted in the US, where a State Department official said: "We take these reports seriously but I don't think we have a body yet."

Although Tawhid and Jihad had threatened to kill the three hostages unless female prisoners were freed from Iraqi jails, the US military says no women are being held in the two prisons specified by the group. Two "high value" prisoners are in US custody, however, accused of working on the ousted Iraqi president Saddam Hussein's weapons programme.

Using bombast familiar from other statements, the internet posting said: "The sons of our nation have slit the throat of the second American hostage after the deadline passed and we will provide you with pictures soon God willing."

It went on to castigate President George Bush, stating: "Oh, you Christian dog Bush, stop your arrogance ... the mujahedin will give America a taste of the degradation you have inflicted on the Iraqi people." President Bush's address to a subdued UN General Assembly was equally uncompromising. After defending the war in Iraq, he said Washington would not negotiate, and vowed not to retreat against an insurgency which he said was likely to bring increased violence in coming months.

He condemned the killing of Mr Armstrong during a meeting in New York with the interim Iraqi Prime Minister, Iyad Allawi.

"We all stand in solidarity with the [remaining] American that is now being held captive," Mr Bush said a few hours before the latest claim was made.

Terrorists believe that "suicide and murder are justified ... And they act on their beliefs," Mr Bush said.

More than a dozen hostages are being held in Iraq and are threatened with death unless their captors' demands are met.

Two French journalists were seized a month ago, and two female Italian aid workers were kidnapped earlier this month.

Another guerrilla group has threatened to kill 10 Turkish workers unless their company stops doing business in Iraq. The firm said on Tuesday that it would do so.

Iraqi police said they found the body of a Turkish driver who had been shot several times, but Turkish media said that militants released another truck driver who had been kidnapped six weeks ago.

Yesterday's statement from Zarqawi's group was similar to the one posted on Monday night before the release of footage of the beheading of Mr Armstrong. The US Central Intelligence Agency determined with a "high degree of confidence" that Zarqawi was the masked militant who read out the lengthy statement before drawing a knife and beheading Mr Armstrong. A CIA official said that the voice on the tape matched that of Zarqawi on other recordings.