IT WAS 9.30am when three men entered Haidar Musa’s sweet-shop and shot him repeatedly in the head as his eight-year-old daughter Zainab crouched in terror behind the counter.

By midday his stricken wife Kahiriya had packed Zainab and four other children into a car with a few possessions and fled their home town of Abu Ghraib for a life of penury in Baghdad, 20 miles to the east.

Eighteen months later, the six of them are living in a room that measures 12ft by 12ft, with a concrete floor. Its contents include a cooking pot, a sewing machine and thin sponge mattresses because this is their kitchen, sitting room and bedroom.

Asked when she intended to leave this squalor and return to the comfortable family home, Kahiriya Musa, 30, is emphatic. “Never,” she declares. “They will kill me if I return.”

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While one of her husband’s killers has been arrested, she says, the other two have joined the Baghdad Brigade, a Sunni militia funded by the American forces which now holds sway in her old neighbourhood.

Members of the Baghdad Brigade receive $300 a man each month from the Americans, who also provide vehicles, uniforms and flak jackets. In return the brigade keeps out Al-Qaeda, dismantles roadside bombs and patrols the area, a task performed with considerable swagger by many of its 4,000 recruits.

The US military is delighted with the results achieved by the brigade in Abu Ghraib and by similar groups in other former “hot spots” of sectarian conflict that have seen a sharp decline in violence.

For Shi’ites such as Kahiriya Musa, however, a Sunni militia represents another potential source of terror in a country where millions have been traumatised by ethnic cleansing.

A 50% cut in car and roadside bombs, shootings and rocket and mortar attacks since June has brought hope that some of the 5m Iraqis driven from home may soon be able to go back. Yet many – Kahiriya Musa among them – are too frightened of the new militias and the ethnic cleansers in their ranks to risk moving.

Officials in the Shi’ite-led government also fear the burgeoning of fresh forces beyond its control. The question being asked in government circles is: have the Americans achieved a short-term gain in security at a cost of long-term pain that may be inflicted by the Sunni militias, which are already threatening to go to war against their Shi’ite counterparts?

The western province of Anbar first witnessed the phenomenon known as “the awakening” – the turning of Sunni tribes against the largely foreign fighters of Al-Qaeda in Iraq.

For General David Petraeus, the American commander, the awakening has proved a powerful force with which to increase the impact of his surge of 30,000 US troops earlier this year.

By allying the US forces with Sunnis opposed to Al-Qaeda, the general has engineered victories over the brutal foreign fighters that seemed almost unimaginable 12 months ago.

US-backed Sunni militias have spread eastwards from Anbar across Baghdad. They already number 77,000, known collectively as “concerned local citizens”. This is more than the Shi’ite Mahdi Army and nearly half the number in the Iraqi army.

Exotically named groups such as the Knights of Ameriya and the Guardians of Ghazaliya strut the streets in camouflage uniforms, brandishing new AK47s that the Americans say they have not supplied.

Last week I entered the western Baghdad district of Ameriya by crossing check-points manned by the eager “knights”. Not only had some of them been members of groups aligned with Al-Qaeda eight weeks ago, but they had now created a virtual enclave surrounded by concrete blast walls.

To be among them without fear of kidnap was to sense the transformation of security in a place that was being torn apart by fighting only last August.

Some wore sinister masks, however, and observers are asking how long it will be before they turn on their Shi’ite counterparts when the Americans start reducing their troops next year.

Sergeant Jack Androski, of the 1st Battalion, 5th Cavalry Regiment, sees things differently. “Ameriya is the safest neighbourhood in all of Baghdad,” he said as he chewed on a falafel and gazed up the suburb’s main commercial street.

“This didn’t exist in May, We lost 17 soldiers on this main street. We used to be hit at least twice a day here and a 500lb bomb flipped one of our Bradleys [fighting vehicles] over.”

Androski paid tribute to the “bravery and determination” of the knights who helped to see off Al-Qaeda. But even Sunni residents see trouble ahead.

One pointed out former members of the Islamic Army – a group once closely associated with Al-Qaeda, whose atrocities included the murder of Enzo Baldoni, a kidnapped Italian journalist – among the knights.

In an Ameriya school last week some of the knights showed that although they may have switched allegiances, they still hold the fundamentalist beliefs that drew them to Al-Qaeda in the first place.

Carrying their weapons, they went from one class to the next, looking for mobile phones with “unIslamic” ringtones. One child with a pop music ringtone was slapped and kicked in the legs as a warning to the others.

Meanwhile, the targets of ethnic cleansing continue to suffer. Habib Haji, a 65-year-old widower from Sab al-Boor, north of the capital, received a letter giving him three days to leave with his daughter Salwa, 15, or die.

“I left immediately,” said Haji, whose 18-year-old son Mehdi had already disappeared after going out to buy some cigarettes.

According to Haji, the death threat came from men who used to be Al-Qaeda members but now form part of the awakening. Even the militia commanders confirm that they have the Shi’ites in their long-range sights after a turbulent few months.

First they tired of Al-Qaeda’s beheadings, bombings and strange demands, such as a ban on salads containing (male) cucumbers and (female) tomatoes, and on ice cubes because the Prophet Muhammad never had them.

Then the militias threw in their lot with the Americans to get rid of Al-Qaeda, but without losing their animosity for the occupying forces that many of them had been fighting.

Now they are starting to think about what happens when the Americans leave and how they can counter Iranian-backed Shi’ite forces. Abu Omar, an intelligence officer with the Baghdad Brigade in Abu Ghraib, was candid.

“Of course the coming war is with the [Shi’ite] militias,” he said. “God willing, we will defeat them and get rid of them just as we did Al-Qaeda.”

Abu Maroof, one of the brigade’s commanders, said that he regarded the Shi’ite militias, which include the Mahdi Army of the radical cleric Moqtada al-Sadr, as more dangerous than the United States. But he is also increasingly hostile to the government of Nouri al-Maliki, which is reluctant to absorb militia members into the official Iraqi security forces.

“If the government continues to reject them, let it be clear that this brigade will eventually take its revenge,” he warned.

It is little wonder that Shi’ite sheikhs have been queueing up this month to air their worries about the Sunni militias to Ahmad Chalabi, a former deputy prime minister who is now in charge of reconstruction and who straddles the sectarian divide.

“Many of the groups in the awakening are the same men who used to kill and displace our people,” one protested. “Any return of refugees is near impossible if this is not resolved.”

Chalabi has come to an accommodation with the Sunni sheikhs of Sab al-Boor, where Haji and his daughter lived: they will get better services – electricity, schools, factories reopened to create jobs – if they guarantee security for 100,000 refugees to return home from temporary shelter in Baghdad.

Several hundred families have already trickled back and their fate will be anxiously monitored. If Sab al-Boor seems safe, thousands more will follow.

Many others dread to think what the Sunni militias will do if the government refuses to have them in the security forces and the Americans leave them to their own devices.

Kahiriya Musa, for one, intends to keep her family close by in the hovel with the concrete floor: “I am afraid for my life and the lives of my children.”

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