Elsewhere, Shia Mehdi Army militiamen clashed with US troops in the capital and in the holy city of Najaf to the south and also engaged in sporadic fighting with the British in Basra, where three soldiers were wounded in a grenade attack.

In Mosul, a US soldier was killed and another wounded Saturday in a mortar attack on the coalition base, the US army announced yesterday. The army said the wounded soldier had been evacuated to the military hospital in Mosul.

US troops have been regularly targeted by insurgents in and around the predominantly Sunni Muslim city, 370 km north of Baghdad, where deposed president Saddam Hussein remains popular.

In the United States, where the administration is under fire during the presidential election campaign over abuse of Iraqi prisoners, Vice President Dick Cheney spoke up for Defence Secretary Donald Rumsfeld. Despite assurances from President George W. Bush that the ill-treatment of prisoners by US soldiers was the "wrongdoing of a few", evidence has mounted of widespread abuses that have contributed to anger among Iraqis at continued US occupation.

A Pentagon official told The Washington Post that new pictures, including video made by soldiers at Baghdad's Abu Ghraib prison depicting "live-action abuse", could be released soon.

That would deepen a global scandal unleashed by images, leaked after months of allegations of ill-treatment by US guards and interrogators, of naked Iraqi detainees being humiliated.

The apparent bomb blast in the Bayaa district of southern Baghdad left body parts strewn around the market and blood and flesh coated on walls.

It was not clear whether the Iraqi police, regarded by guerrillas as collaborators, had been the intended target. A US military convoy had passed by shortly before. The unassuming neighbourhood, home to both Sunni and Shia Muslims, was not an obvious target.