US air strikes killed an estimated 40 anti-US fighters in western Iraq on Saturday.
Seven precision-guided missiles were fired at heavily armed fighters near al-Karabla, close to the town of Qaim, the US military said in a statement.
Earlier, 11 people were killed and 29 others injured after a car bomb exploded overnight in a street in a Shia area of Baghdad.
Police said the target of the bomb was not clear. The car, parked in the street in northwest Baghdad, exploded at about 11pm (1800 GMT) on Friday.
This was considered the worst day of violence since the Iraqi authorities launched a major operation called Operation Lightning on 29 May, aimed at hunting down anti-US fighters.
In another attack, 11 Iraqi construction workers were killed when their minibus came under fire south of Baghdad on Saturday, police said.
"Eleven Iraqis were killed and three others wounded around 9am when men aboard two cars opened fire on a minibus taking construction workers from Jbala, 70km south of Baghdad, to the capital," Captain Said al-Kraimi 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, Aljazeera reported.
Body parts littered the barracks area close to the Interior Ministry and police academy which houses the Wolf Brigade, a military-style force of several hundreds, mainly drawn from the capital's Shia poor.
The pick-up truck blast wounded
In another incident on Saturday, Aljazeera said 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.
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 (US) patrol returned fire, killing two occupants, wounding two more and setting their car on fire"
Lt Jamie Davis,
US military spokesman
"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.
Jabr said Operation Lightning had
led to 1318 arrests
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.
"Operation Lightning has forced the terrorists to flee outside Baghdad," Jabr told a news conference. "For us, it has been more than 90% successful."