ABU Musab al-Zarqawi has long been viewed as the key figure in the insurgency sweeping Iraq. By capturing him it was once thought that the new government would gain control of even the most hostile areas of the country.
But the power struggle to succeed al-Qaeda's leader in Iraq has shown that the organisation is resilient enough to withstand the blow.
Since being wounded last week it has emerged that Iraq's most wanted terrorist has fled the country for emergency surgery after an American air strike left him with shrapnel in his chest.
According to a senior insurgent commander in close contact with Zarqawi, who has a $25m bounty on his head after being blamed for suicide bombings, assassinations and the beheadings of hostages, including Liverpudlian Ken Bigley, he is believed to be in Iran.
He has suffered from bouts of high fever since being wounded as he fled the American offensive near Al-Qaim in northwestern Iraq, the commander said. Although his condition has stabilised, supporters are said to be preparing to move him to another "non-Arab" country for an operation to remove the shrapnel.
The absence of triumphalism in Washington over the shooting of Zarqawi indicates that the US no longer considers that the insurgency can be beaten through the removal of one man.
There were no shortage of candidates vying to take over from Zarqawi.
The power struggle surfaced on the internet, which al-Qaeda uses as its main means of communication and propaganda with a skill surprising for an organisation that wants to return to the purity of the seventh century.
Analysts say that the insurgency can carry on with or without Zarqawi's guiding hand, as it showed last week when it downed a US helicopter, killing two soldiers.
"The organisation has proved to be somewhat resilient," said Brigadier General Carter Ham, commander of Task Force Olympia, who directed thousands of troops during 13 months of operations in Zarqawi's former stomping ground of northern Iraq. "We ought not to expect that the organisation will crumble and cease to exist" as a result of Zarqawi's death or capture, he added.
Diaa Rashwan, an expert on radical Islam at Egypt's Al-Ahram Centre for Political and Strategic Studies, said: "The real danger in Iraq is that you have more than 50 attacks a day, with some made by Zarqawi and 80% made by others.
"It's not really a problem of who will be the successor. He's a symbol for a kind of network of small Islamic groups which share tactics and ideology."
The dispute over the leadership started with an internet announcement in the name of the media coordinator for al-Qaeda's Iraq branch, Abu Maysara al-Iraqi, that Zarqawi had been wounded and that Muslims should pray for him.
There followed another statement signed by an unfamiliar name, Abu Doujanah al-Tunisi of the media committee for al-Qaeda's Iraq branch, claiming that a Saudi militant known as Abu Hafs al-Qarni had been made the group's interim leader - or "deputy of the holy warriors" - until Zarqawi recovered from his wounds.
Al-Qarni "is known for carrying out the hardest operations, and our sheikh would choose him and his group for the tough operations", it said.
A Western diplomat said: "The split itself reveals the extent to which al-Qaeda, which was unknown in Iraq before the US-led invasion, has built an organisation with different departments. A number of potential successors are being mooted, showing that this is not a one-man band. You might even detect shadowy signs of a government-in-waiting.
"The US is no longer giving the impression that if they can remove Zarqawi they will have got rid of al-Qaeda in Iraq. After initially building him up by putting a huge price on his head, they are now playing down his significance."
The widely respected pan-Arab newspaper Al Hayat reported that a number of candidates were competing to succeed Zarqawi. Al-Qarni was not among those named, but Abu Maysara al-Iraqi, the man who ruled him out, is on the list.
Sources in Jordan, close to Zarqawi, also name Abu Maysara al-Iraqi as a potential successor, but also add another contender, Abu al-Dardaa al-Iraqi, an al-Qaeda operative in Baghdad.
One reason for the insurgency's resilience is that despite Zarqawi's Jordanian lineage - and the attempt by the US to foster the belief that almost all suicide bombers are foreigners - the insurgency is largely homegrown.
Its principal supporters are Iraqis formerly loyal to Saddam Hussein and Iraqis devoted to an extreme radical strain of Sunni Islam.
"The majority of people blowing up things, assembling car bombs and financing the blowing up of Humvees or attacks on police stations are Iraqi," said an American diplomat. "There is also a foreign element, a very pernicious foreign element, which is one of the reasons it's so difficult to degrade it."
Steven Emerson, a terror analyst with the Washington-based Investigative Project and author of the book American Jihad, said: "It's the same as we've seen in Pakistan and Afghanistan - hundreds of millions of dollars in collective rewards for Bin Laden and Zarqawi and others have not produced anything in terms of people coming forward in exchange for money.
"There is a deeply entrenched network. It comes from Syria. It comes from Saudi Arabia. There are some people transiting through Jordan. The Syrians, in particular, have a lot of blood on their hands."
However, he added of the wounding of Zarqawi: "Because he's such an on-the-ground commander, and so control-oriented, this could have a major effect in disrupting the insurgency's coordination and operations. Zarqawi was the glue that held the organisation together. It was Zarqawi, Zarqawi, Zarqawi. Not like Bin Laden, who had a whole chain of command that he could rely on."
Another reason the insurgency is proving difficult to defeat is that it has perfected the technique of 'ghosting away' from major confrontations with US forces only to raise its flag in other cities.
Since the assault on Fallujah last November, which was supposed to 'break the back' of the violence, the insurgency has flared repeatedly.
"It's like toothpaste: you squeeze somewhere, and it just pushes the insurgents somewhere else," said Toby Dodge, an Iraq expert at the International Institute of Strategic Studies in London.
• A senior Pakistan army commander said yesterday that al-Qaeda-linked militants had been eliminated in the country's South Waziristan tribal region after months of gun battles around this peak and in nearby mountains last year.
Major General Niaz Khattak, who is leading the troops hunting militants, said that between 500 and 600 al-Qaeda linked militants were believed to have been hiding in the region.
"According to our intelligence reports, we now think there are absolutely none in South Waziristan," Khattak said.