Minister Malik Dohan al-Hassan is responsible for detaining Baathists

The minister, Malik Dohan al-Hassan, was uninjured.

The blast rocked an intersection in central Baghdad, just 500m from the minister's home, and a plume of smoke was seen rising over the city.

The bomb struck the tail-end of his convoy of cars as he was leaving home, setting off secondary fires.

"A car was parking on the opposite direction of the road, when the driver saw us and exploded himself," Loae Hassan, one of the minister's bodyguards, told the Associated Press.

A militant group linked to top al-Qaeda suspect Abu Musab al- Zarqawi - Tawhid and Jihad - said it had carried out the attack against "the justice minister of the apostate government".

Wave of attacks

Insurgents have repeatedly targeted top Iraqi officials and US-led coalition forces in a wave of car bombings and suicide attacks.

Four of the justice minister's bodyguards died in the blast

A US soldier was killed and another wounded on Saturday when a roadside bomb exploded near Baiji, 180km (110 miles) north of Baghdad, the US Army said.

And in Mahmudiyah, 30km (20 miles) south of Baghdad, two people were killed when a car bomb exploded outside an Iraqi National Guard headquarters.

Dozens of others were injured when the explosion tore through a queue of volunteers waiting to sign up.

The blasts came on the 36th anniversary of the coup that brought Saddam Hussein's Baath party to power in Iraq.

On Wednesday at least 10 people were killed and about 40 injured in a car bomb explosion in Baghdad - the first major attack in the capital since the handover of sovereignty on 28 June.

ATTACKS SINCE HANDOVER 17 July - Car bomb in Baghdad targets Iraqi justice minister, killing four of his guards 15 July - Car bomb targets police station in Haditha, west of Baghdad, killing 10 14 July - Governor of Mosul killed in ambush 14 July - Car bomb explodes near seat of government in Baghdad, killing 10 and wounding 40

Hours later the governor of Mosul, Usama Kashmula, was killed when his convoy was ambushed, in an attack claimed by a group linked to Jordanian-born militant Abu Musab al-Zarqawi.

Iraqi Prime Minister Iyad Allawi has vowed to crush the insurgents behind the attacks.

On Thursday he announced plans for a new intelligence unit to "annihilate those terrorist groups".

In a bid to contain the spiralling violence Iraq has introduced tough new laws allowing the government to impose martial law in certain areas, declare curfews, set up checkpoints and detain suspects.

The violence threatens to trigger an Iraqi brain-drain, according to Ismael Zayer, editor in chief of al-Sabah al-Jadid, a Baghdad-based newspaper.

He told the BBC's World Tonight programme that doctors, professors and economists had begun to lose confidence in Iraqi society because of the insecurity and many had already decided to emigrate to the Gulf states and Jordan.