Elsewhere, three soldiers serving in the US-led occupation force and two Iraqi security personnel have been killed in separate attacks across the country that have left dozens of troops, resistance fighters and civilians wounded.
According to Aljazeera's correspondent, a roadside bomb detonated as a US convoy passed through Baquba, northeast of Baghdad, on Saturday.
An Iraqi street hawker and a child were reportedly among the dea and five rubbish collectors were wounded in the blast. There were no reported casualties among the US troops.
"The peddler was selling gas cylinders and the others were dustmen. As far as we know, a US convoy was the target but the bomb exploded before it arrived," said a police spokesman, first lieutenant Ali Husayn.
Meanwhile, two US soldiers were killed and three injured by a roadside bomb near the Iraqi city of Samarra, 100km north of Baghdad, a spokesman for the US Army First Infantry division said on Saturday.
The spokesman said the attack took place at 0555pm (1355 GMT) on Friday during a military patrol. He said the condition of the three wounded soldiers was unknown.
More than a dozen Polish soldiers
have died in clashes in Iraq so far
And a Polish soldier was reported killed and six others wounded on Saturday in a car bomb attack near Hilla in southern Iraq.
The parked car exploded as a 19-truck convoy under the protection of Polish troops was driving by, Colonel Artur Domanski, the spokesman for the occupation force under Polish command, said.
He added that Polish soldiers shot and killed several attackers after the bombing, which occurred close to midday (0800 GMT).
The latest attack takes to 14 the number of Poles killed in Iraq since the start of the US-led war - 10 soldiers and four civilians.
Meanwhile, a senior police officer was killed early on Saturday in the city of Ramadi, west of Baghdad.
Col Saad Samir al-Dulaimi, head of the crime-fighting unit in the city, was shot and killed as he left home at about 0830am (0430 GMT), police captain Hasan Qadhim said.
And an Iraqi soldier was killed when an explosive device detonated near an Iraqi National Guard checkpoint in al-Sukkar neighbourhood in the northern city of Mosul, sources told Aljazeera.
Five others, including three civilians, were injured. A number of cars were also damaged in the explosion, the sources added.
For three hours overnight, US forces and militiamen clashed around a Kufa mosque and court house, just 10km east of Najaf, according to fighters loyal to Shia leader Muqtada al-Sadr.
One person was killed and 12 others - militiamen and civilians - were wounded in the clashes, Dr Muhammad Abd al-Kadhim of Kufa hospital said.
One person was killed in fighting
around a mosque in Kufa
A huge hole was torn in the outer wall of the Maitham al-Tamam compound in the process. Part of the court building opposite was blackened and gutted by fire, with caked blood smeared on the windows, said an AFP correspondent.
Militiaman Abu Muhammad al-Hilu said fighters had fired a rocket-propelled grenade at the court building, being used as a US post, and accused US forces of trying to storm the mosque.
A US military spokeswoman had no immediate information about the incident.