A roadside bomb has exploded near a convoy carrying Iraqi generals in a Shi'ite militia stronghold in the southern city of Basra.

No casualties were reported in Wednesday's blast, which was reported hours later by Iraqi Defense Ministry spokesman Mohammed al-Askari, who was traveling in the convoy.

He said an Iraqi cameraman also was shot and wounded in the leg as he was filming events in the Hayaniya neighborhood.

The area was the scene of major clashes last week between Iraqi security forces and Shi'ite militias loyal to radical cleric Muqtada al-Sadr.

A tense calm is reported holding for a third day in Basra today.

Police in Baghdad say a roadside bomb aimed at a U.S. convoy killed at least three Iraqi civilians and wounded 13 near a restaurant in the Sadr City area.

U.S. military spokesman Kevin Bergner told a news conference last week's fighting and high Iraqi death toll shows there is still much more work to do, to develop and strengthen the capabilities of the Iraqi security forces, some of whom he said are "not up to the task."

However, Bergner added that the fact the security services carried out the operation at all, with only limited involvement of U.S. and British forces, was in itself a positive development.

Some information for this report was provided by AFP, AP and Reuters.