Radical Shia cleric Moqtada Sadr has offered to withdraw his militia from the holy Iraqi city of Najaf.
By Verity Murphy
BBC News Online
The fighters, called the Mehdi Army after a messianic figure in the Shia tradition, have been fighting coalition forces since early April.
But despite their name, they are not actually an army.
Analysts describe them as a rag-tag band of armed part-time volunteers, with little training and discipline.
It is this amorphous set-up that gives the clearest indication of what will happen to the Mehdi Army after they quit Najaf.
"In Iraq many people have guns, every family has a gun, and these people are simply armed Shias from urban areas," Joost Hiltermann, director of the International Crisis Group, a think-tank based in Amman which has been studying the militias, told BBC News Online.
The Mehdi Army have lost hundreds in the weeks of urban fighting
"As they aren't a real army there is nothing to disband. What they are likely to do is just melt away, they will go back to their homes and their jobs and just keep their guns with them," he added.
According to Mr Hiltermann the Mehdi Army fighters are amongst the poorest of the Iraq's Shia population: "They are the disenfranchised, the dispossessed. They feel they haven't gained much from the ousting of Saddam Hussein and the American occupation and so they see following Moqtada Sadr as a way out."
The Mehdi Army, which also engaged in fighting in Iraq's other holy city Karbala, is thought to have numbered less than 10,000 fighters when the insurgency began.
But now it is much depleted. They have lost many hundreds of fighters in pitched battles with US-led coalition forces.
Observers say the heavy casualty toll will have contributed to Mr Sadr's decision to negotiate a truce.
In light of the MA's set-up the huge disparity between their losses and those of the Americans is unsurprising. Although a few of the militia may be former soldiers, for the most part none of them have ever been trained for war.
"They have no real chain of command, no discipline and no training," said Mr Hiltermann.
But what the Mehdi Army lack in training, they make up for in passion and allegiance to their leader.
"For most of his followers Moqtada Sadr is the voice of the dispossessed - he is the voice of their aspirations and they hope that he will lead them to greater economic and political power," Mr Hiltermann explained. "Whether of course he can deliver that is another story."
In attempting to make good on those promises Mr Sadr took a controversial step, sending his forces, most of whom come from Baghdad, into Iraq's holy cities.
There was outrage when Imam Ali's shrine in Najaf was damaged
This has proven divisive among Iraq's Shia population and could undermine the support that the firebrand Shia cleric has enjoyed.
"Fighting in the holy cities carries great risk. Any damage done to the shrines will be blamed on the US and that could inflame not only Shias in areas of Iraq, but elsewhere too - places like Iran, Bahrain, Saudi Arabia or Lebanon. It would be a bit like an attack on The Vatican," said Mr Hiltermann.
But large sections of the quiescent Shia community hold Mr Sadr equally to blame.
Many believe that by sending in his forces to Najaf and Karbala, Mr Sadr attracted trouble, luring the US forces into fighting just yards from some of the country's holiest sites.
In Karbala, which Mr Sadr's forces left after weeks of urban fighting, locals have been outraged by the fighting, which defiled mosques and kept pilgrims, the main source of income for the holy cities, away.
"We do blame them both," local shop owner Ghassen Meri told the International Herald Tribune. "The Mehdi Army, they were using the shrines as shields."
But despite their waning popularity and reduced numbers the US will be keen to ensure the Mehdi Army does not stir up trouble again in the future.
"In order to prevent their re-emergence the US may offer some of the fighters positions in the new Iraqi army, so they haven't gone away, but will re-appear in a different guise," Mr Hiltermann said.