A 13-year-old girl became the youngest suicide bomber to wreak havoc in Iraq yesterday, killing five Iraqi guards in a town that has become notorious for deadly attacks by women bombers.

The girl blew herself up in Baquba, on the same day that a car bomb exploded in Baghdad, killing about 30 people and shattering a fragile sense of calm in the capital.

The carnage was compounded by a male suicide bomber who joined the crowd of rescue workers, bystanders and frantic relatives of victims before blowing himself up in a follow-up explosion.

Police and medics said the Baquba bomber was a girl of just 13 years old, making her the youngest person yet to blow themselves up in the conflict.

In the past militants have exploited women and youngsters for use as suicide bombers. In one case child passengers were used as decoys to enable a car bomb to be smuggled past unsuspecting US soldiers before it was detonated with the young boys still inside.

Insurgents have also used children to bury roadside bombs and even fire rocket-propelled grenades at US forces. This callous deployment of youngsters has helped to fuel a backlash against groups such as al-Qaeda within the Sunni community.

The target of the teenage bomber was a patrol by the Sons of Iraq, former Sunni insurgents who have turned on al-Qaeda.

Many of the victims of the car bombing in the Sunni area of Addumiyah in northern Baghdad were schoolgirls, travelling in a minibus.

“Innocent and simple people were gathering to have breakfast or shop in the nearby area. A minibus which was driving past was also hit and four or five of its passengers were killed,” said a bystander. “How can you explain this act? This is not a military unit, not a military barracks. There is nothing there.” Witnesses described the minibus torn apart by shrapnel, its bloody floor scattered with girls' shoes.

US military officials said the blast appeared to be the work of al-Qaeda, which, though on the wane, is still a potent and deadly force in Iraq.

A number of policemen and soldiers were killed when they rushed to help the wounded, only to be hit by the second bomb minutes later.

Hundreds of children have died in countless bombings, often when car bombers target US military vehicles in urban areas, as children gather around hoping for sweets or treats from the American soldiers.

Baquba has been struck by a wave of women suicide bombers in recent months, often the widows of al-Qaeda members or Islamist extremists who have themselves been killed fighting against the Americans or the Shia government forces. About 30 women have blown themselves up this year, compared with 8 in 2007.

The teenager's attack on the Sons of Iraq coincided with the first payment by the Government to the Sunni militias, who have until now been funded by the US military who helped to recruit and train them.

The Government has been highly suspicious of the parallel army that has emerged under American supervision, and consists largely of fighters the regime has long viewed as terrorists.

There had been speculation that the Government could refuse to pay them or to offer them jobs in the regular security services, risking a militia backlash.

As about 54,000 militiamen received their wages, US Brigadier-General Robin Swan said: “This is really a tremendously important day and a manifestation of the reconciliation process that is happening in Iraq. The real proof of the pudding is in the payday.”

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