A female Iraqi translator and a male bodyguard were killed and a German man seriously wounded on Saturday when US soldiers opened fire at their car, Aljazeera's correspondent reported.
The shooting occurred in the aftermath of a roadside bomb blast near Falluja, 50kms west of Baghdad.
Elsewhere, a US military spokesman said three Iraqi civilians were killed and two wounded when a roadside bomb hit two civilian vehicles, which then came under fire on a highway, 80km west of Baghdad.
An official at a local hospital said one of the wounded was a Westerner while his Iraqi translator was among the dead.
Across the country, about 20 US troops have been injured in Iraqi resistance attacks, which included the shooting down of a US helicopter.
Six US soldiers were wounded in two separate attacks in the Baquba region, northeast of Baghdad, on Saturday.
US soldier guards captured truck
carrying RPGs in Baghdad
Two were wounded in a roadside bombing of their convoy, near a bridge in central Baquba, 65km northeast of the capital.
US forces detained 15 local residents, tied their hands behind their backs and forced many of them to lay face down on the ground, witnesses said.
Elsewhere in the region, four US soldiers were wounded in a rocket-propelled grenade (RPG) attack on their convoy in the industrial area of al-Hai al-Suni, 6km southwest of Baquba. The attack occurred at 4pm (1300 GMT).
In Khalidiya, west of Baghdad, five US soldiers were wounded after an explosion and shootout with resistance fighters at 7:15pm (1615 GMT), locals told AFP. The blast was followed by a rocket-propelled grenade attack and a firefight, they said.
Earlier, five US soldiers were wounded when a US military Black Hawk helicopter came down in an RPG attack. The helicopter crash-landed near the town of Tikrit, former President Saddam Hussein's birthplace.
Black Hawk carries injured troops
from site of crash near Tikrit
US military spokesmen said they were unsure whether the aircraft was shot down or was hit by an RPG after it landed. But a doctor said one of those injured was suffering from shrapnel wounds in both the arms and legs.
The helicopter was seen by an AFP photographer, trailing smoke minutes after a loud explosion. The sound of small arms fire was also heard from the direction of the emergency landing, the French news agency reported.
US assistant defence secretary, Paul Wolfowitz, on a tour of Iraq, visited Tikrit only hours before the attack on Saturday.
Taekwondo team shot
Elsewhere, the US military confirmed three soldiers were wounded in a bomb attack in Baghdad, AFP reported.
Captain Ty Wilson of the 1st Armoured Division said a makeshift bomb, possibly a mortar round detonated by remote control, exploded at dawn on Saturday in the southwest of the capital.
In another incident, 11 members of a martial arts team were wounded, three of them seriously, when unknown assailants opened fire on their bus near the northern oil town of Kirkuk.
The Kurdish taekwondo team was heading back to Kirkuk from a Baghdad tournament when they came under attack. Doctors said three of the team members were in serious condition and had been operated on five times.