Seven precision-guided US air strikes on the outskirts of the town of Karabilah killed the insurgents who were stopping vehicles at gunpoint and threatening Iraqi civilians, said a US military statement.

The strikes came Saturday, after at least 43 people were killed in attacks in Iraq over the past 24 hours as a spate of bomb attacks shattered a relative calm in Baghdad since US and Iraqi forces launched a sweep for insurgents three weeks ago.

The military said there were no US casualties when Marines engaged large groups of insurgents armed with rocket-propelled grenades, machine guns and AK-47 assault rifles.

The US military said there were no reports of civilian casualties. It was not immediately possible to confirm the insurgent casualty figures independently.

While US forces struck guerrillas in their heartland of Anbar province, a former Iraqi police commando blew himself up in a failed bid to assassinate the leader of the anti-insurgent Wolf Brigade in Baghdad, Major General Mohammed Qureishi, killing three other policemen in the attempt, the Interior Minister said.

The motive was unclear but the mainly Shia Muslim force has been at the centre of controversy about aggressive methods and accusations of a sectarian "dirty war" on minority Sunnis.

In an Internet claim of responsibility, the Sunni insurgent group linked to Osama bin Laden's al-Qaeda said: "Our brother would not accept the humiliation of ... Sunni men and women."

Body parts littered the compound near the Interior Ministry which houses the Wolf Brigade. One officer was hurt. al-Qaeda in Iraq, responsible for dozens of suicide bombings, named the attacker as Abu Mohammed al-Dulaimi, apparently a Sunni Iraqi.

The force, set up by Qureishi last year under formal Interior Ministry control, comprises hundreds of commandos drawn mainly from poor Shia districts of the capital. With their distinctive wolf's head insignia, they have become folk heroes to some Shias but an object of fear and mistrust for Sunnis.

The US Council on Foreign Relations suggested last week it was "the most feared and effective commando unit in Iraq."

In a separate statement, al-Qaeda's wing in Iraq said its leader Abu Musab al-Zarqawi supervised a series of raids in the country on Saturday in response to operations by Iraqi security forces and US troops and in revenge for "aggressions ... against our Sunni brothers in the Sunni area."

"Your brothers in al-Qaeda Organisation launched important operations and attacks today and under the direct supervision of our sheikh Abu Musab al-Zarqawi ...," the group said in a statement posted on an Islamist Web site.

After reports Zarqawi had been wounded in a US missile attack, the al-Qaeda Organisation for Holy War in Iraq confirmed last month he had been hurt but was in good health and leading operations.

Qureishi denies accusations his men have attacked innocent members of the Sunni Muslim minority that dominated the Shias under Saddam Hussein. He denies killing Sunni clerics.

Some Sunnis compare the Wolf Brigade to sectarian militias.

The Shia-led government has recently called for a continuing role for militias such as the Kurdish peshmerga in the north of Iraq and the Badr Brigade, the armed wing of the Shia party to which Interior Minister Jabor belongs.

The US-led occupying forces are uneasy about that but officials say the fighting readiness of such militias make them useful elements in the fledgling government's armoury.

Sunni leaders are negotiating with the Shia-dominated parliament for a bigger role on a committee charged with drawing up a constitution. Violence in Sunni areas and boycott calls meant few of the 20 percent minority voted in January's election, leaving them under-represented in parliament.

On Friday, the main Sunni political grouping rejected an offer of 15 seats on a committee of 69, demanding 25 places.

The Shia chairman of the committee, Humam Hammoudi, told Reuters on Saturday the Sunnis were being "unreasonable" in their demands. Since the aim was to reach consensus, precise numbers of delegates were not so important, he said.

"Increasing the numbers on the committee ... would open the door wide to endless talk," Hammoudi said, repeating the offer of 15 seats for the Sunnis which the government has endorsed.

With drafting already under way by the present committee of 55, Hammoudi said he was confident of meeting an Aug. 15 deadline for proposing a draft text.

Shias and leaders of the 20 percent Kurdish ethnic minority have made clear they want Sunni involvement to help defuse the insurgency ravaging Baghdad and Sunni areas to the west and north. Jabor said on Saturday the government was open to talks with any movement which forswore violence.

After a relative calm in recent days, possibly due in part to a crackdown by US and Iraqi forces, the capital saw several attacks. A car bomb exploded in a street in a Shia area of Baghdad overnight, killing 11 people and wounding 29.

Eleven people died and two were wounded when gunmen opened fire from two cars on a minibus carrying labourers toward the city. The attack happened near Latifiya, in the troubled area to the south that has become known as the "triangle of death."

A suicide attacker blew up a truck bomb outside the Slovakian embassy, wounding four Iraqis. That attack was also claimed by Abu Musab al-Zarqawi's al-Qaeda in Iraq group.