Eleven people have been killed and 29 others injured after a car bomb exploded overnight in a street in a Shia area of Baghdad.

Police said on Saturday the target of the bomb was not clear. The car, parked in the street in northwest Baghdad, exploded at around 11pm on Friday.

This is considered the worst case of violence since the Iraqi authorities launched a major operation called Operation Lightning on 29 May, aimed at hunting down anti-US fighters, blamed for fuelling the violence. 

In a separate attack, 11 Iraqi construction workers were killed when their minibus came under fire south of Baghdad on Saturday, police said.

Elsewhere in Baghdad, a bomber wearing the uniform of Iraq's high-profile Wolf Brigade police force killed eight officers and wounded 12 others at the commando unit's headquarters.

Guards shot

In another incident on Saturday, one Iraqi was killed and another wounded when unidentified armed men opened fire at their car in al-Aamiriya neighbourhood, west of Baghdad.

The two Iraqis were working for Iraqna, a telecommunication company.

Also, a bomber in a pick-up truck blew himself up outside the Slovak embassy in Baghdad on Saturday, wounding four people.

In the day's other major incidents, US soldiers shot dead two Iraqis and wounded two others in Baghdad when their car came too close to an American armoured patrol, the military said.

Iraqi police Major Musa Abd al-Karim said the victims were Iraqi security guards driving to work in northern Baghdad's Shula neighbourhood at about 6.30am and mistakenly shot by US soldiers.

He did not say which company they worked for.

Lead vehicle

US military spokesman Lieutenant Jamie Davis said the Iraqis were driving too slowly in front of a lead vehicle in an American convoy.
An American soldier in the lead vehicle fired a warning shot to make the Iraqi vehicle move away, but its occupants returned fire on the convoy and sparked a gun battle, Davis said.

"The patrol returned fire, killing two occupants, wounding two more and setting their car on fire," Davis said, adding the American soldiers left the scene without stopping.

Another American patrol returned shortly after and found "multiple AK-47s" inside the vehicle and took the wounded men to a hospital, Davis added.

In yet another incident that took place on Saturday, Aljazeera reported that a roadside bomb exploded on the main road in the Iraqi western city of Haditha, destroying a US tank and two Humvee vehicles.

Witnesses said two US soldiers were killed, but the US military has yet to comment on the incident.

Operation Lightning

Meanwhile, Iraqi Interior Minister Bayan Jabr has claimed that a two-week old counterinsurgency campaign was a success and expressed confidence that the Shia-led government would bring Iraq under control within six months.

Jabr said that an ongoing campaign code named Operation Lightning to drive anti-US fighters out of Baghdad had led to 1318 arrests, and claimed it was showing some success in drastically reducing the number of car bomb attacks in the capital.

PHOTO CAPTION

Bound bodies lie along a roadside near Qaim, Iraq, a town near the Syrian border, in this image made from video Saturday, June 11, 2005. (AP)