THE hunt for Abu Musab al-Zarqawi, the terrorist leader, is set to intensify after the capture of several of his fighters who are said to have admitted murdering the British aid worker Margaret Hassan.

Adding urgency to the search was the kidnapping yesterday of another Western hostage in Baghdad, an Australian seen on videotape pleading for his life.

The Jordanian-born terrorist leader is believed to have beheaded Eugene Armstrong, the American colleague of Kenneth Bigley, the British hostage murdered by his captors, last September. Al-Zarqawi has a $25 million (£13.1 million) price on his head and narrowly evaded capture in February, US officials say.

The near-miss occurred as the man whom Osama bin Laden, the al-Qaeda leader, has dubbed his “emir”, or prince, in Iraq was heading from the area around Fallujah — his main stronghold until American forces stormed the city in November — to a meeting in Ramadi, one of Iraq’s most dangerous cities, in the western desert.

Undercover American troops were waiting to arrest him, but al-Zarqawi’s vehicle sped off when they stopped a scout car preceding him. The troops pursued the vehicle and an unmanned Predator drone tracked it from the air, but al-Zarqawi is thought to have jumped out when the vehicle went under a bridge.

The American troops caught up with the vehicle several miles later and found al- Zarqawi’s laptop computer, about $104,000 and two of his aides. One of the men captured was identified as Talib Mikhlif al-Dulaimi, also known as Abu Qutaybah, who arranged safe houses and transportation for the al-Zarqawi network and passed packages and funds, Iraqi officials said. The other man was identified as alZarqawi’s driver, known as Abu Uthman.

American and Iraqi forces have set up units to hunt for al-Zarqawi, a petty thug who discovered radical Islam in a Jordanian prison and trained in al-Qaeda camps in Afghanistan. Since the war in Iraq began he has gradually eclipsed bin Laden, becoming a focus for hardline Islamists who see the insurgency as a prime battleground for fighting US forces.

Al-Zarqawi’s group, al- Qaeda Organisation in the Land Between The Two Rivers, regularly claims responsibility for suicide car bombings and attacks on US bases. US officials believe that many are the work of other cells.

Some Iraqis, fighting purely to end what they perceive as a foreign occupation, say that they do not support al- Zarqawi’s methods of indiscriminate bombings, killing civilians far more frequently than US troops. In Ramadi they have put up posters threatening the Islamists and denouncing their tactics, local people say.

Many are also suspicious of al-Zarqawi’s alleged aim of fomenting civil war between his fellow Sunnis and the majority Shia, whom Wahhabis, the radical brand of Sunni Islam that spawned al-Qaeda, consider to be apostates.

US officials believe that they are getting closer to al-Zarqawi, but acknowledge the canniness of their quarry. General Richard Myers, the chairman of the US Joint Chiefs of Staff, said last week: “I think in general the intelligence is getting better. Having said that, we still don’t have al-Zarqawi.”

Last night it appeared that al-Zarqawi may have another card to play: a videotape showed a kidnapped Australian who identified himself as Douglas Wood begging for his life and surrounded by gunmen. Although it was not clear whether an al-Zarqawi affiliated group was holding the man, al-Qaeda terrorists have bought hostages from criminal gangs and beheaded them.

Mr Wood said on the video that he had come to Iraq almost a year ago to work on reconstruction projects with the American military. He appealed to President Bush and John Howard, the Australian Prime Minister, to order coalition forces out of Iraq. “My captors are fiercely patriotic, they believe in a strong, united Iraq looking after its own destiny,” he said. “They [the Iraqis] are strong, they will be [able to] . . . look after themselves against their neighbours. Please help me. I don’t want to die.”

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