ROBERT FISK: Sergeant's suicidal act of war has struck fear into Allied hearts

Sergeant Ali Jaffar Moussa Hamadi al-Nomani was the first Iraqi combatant known to stage a suicide attack. Not even during the uprising against British rule did an Iraqi kill himself to destroy his enemies.

Nomani was also a Shia Muslim – a member of the same sect the Americans faithfully believed to be their secret ally in their invasion of Iraq. Even the Iraqi government initially wondered how to deal with his extraordinary action, caught between its desire to dissociate themselves from an event that might remind the world of Osama bin Laden and its determination to threaten the Americans with more such attacks.

The details of the 50-year-old sergeant's life are few but intriguing. He was a soldier in the 1980-88 Iran-Iraq war and volunteered to fight in the 1991 Gulf War, called the "Mother of All Battles" by President Saddam Hussein, who believes he was the victor. Then, though he was overage for further fighting, Nomani volunteered to fight the Anglo-American invasion. And so it was, without telling his commander and in his own car, he drove into the US Marine checkpoint outside Najaf.

President Saddam awarded him the Military Medal (1st Class) and the "Mother of All Battles" medal. The dead man left five children, a widow and a place in the 2,000-year history of Iraqi resistance to invasions. A US spokesman said that the attack "looks and feels like terrorism", although, since Nomani was attacking an occupation army and his target was a military one, no Arab would ever believe this.

Within hours of his death, Taha Yassin Ramadan, the Iraqi Vice-President, was talking like a Palestinian or Hizbollah leader, emphasising the inequality of arms between the Iraqis and the Americans.

"The US administration is going to turn the whole world into people prepared to die for their nations," he said. "All they can do now is turn themselves into bombs. If the B-52 bombs can now kill 500 or more in our war, then I'm sure that some operations by our freedom fighters will be able to kill 5,000."

It was clear what this meant; the Iraqi leadership was just as surprised at Nomani's attack as were his American victims.

But the Americans would do well to understand what this new development means. Suicide bombers – whether they be the Shia Muslim Lebanese successfully evicting Israel's army of occupation or the Palestinians destroying Israel's sense of security – are the ultimate weapon of the Arabs. The US first understood its power when suicide bombers struck the American embassy in Beirut in 1983 and the marine barracks in Beirut on 23 October the same year, when 241 American servicemen died. Only when Arabs bent on a far more devastating suicide mission launched their attacks on 11 September 2001 did Washington finally realise that there was no effective defence against such tactics.

In a strange way, therefore, 11 September at last finds a symbolic connection with Iraq. While the attempts to link President Saddam's regime with Osama bin Laden turned out to be fraudulent, the anger that the US has unleashed is real, and has met the weapon the Americans fear most. Most suicide bombers are younger than Nomani and unmarried. But someone must have helped him to rig the explosives in his car, must have taught him how to set off the detonator. And if this was not the Iraqis, as they claim, then was there an organisation involved of which both the Americans and the Iraqis know nothing?

There was some talk by Vice-President Ramadan of "the martyr's moment of sublimity", an expression hitherto unheard of in the Baathist lexicon. General Hazim al-Rawi of the Ministry of Defence recalled that the dead man bore the same name as "the Imam Ali" and announced that the new "martyr Ali has opened the door to jihad".

He said that more than 4,000 volunteers from Arab countries were now in the country and that "martyrdom operations will continue not only by Iraqis but by thousands of Arabs who came to Baghdad".

Suddenly, it seems, Islam has intruded into this very nationalistic war of liberation – for that is what it is called here – against the Americans.