Gunmen shot dead two German civilians and two Iraqis in an attack south of Baghdad today.
Police said the victims were attacked near the town of Hilla, 60 miles south of Baghdad.
In another shooting today, attackers killed the sister of an Iraqi translator working for the US army in Mosul and wounded her brother.
Yesterday, guerrillas opened fire on a car carrying US civilians in the northern city of Mosul. Three were killed instantly and a fourth died in hospital, the US army said. The Southern Baptist International Mission Board, based in Virginia, said the victims were missionaries.
Witnesses said the missionaries had been driving through Mosul in a civilian vehicle without a military escort.
Last Tuesday, two USA civilians seconded from the defence department and their Iraqi translator were shot dead in a road ambush on the road between Hilla and Kerbala. They were the first American employees of the US-led civilian administration to be killed in Iraq.
The US military said six people had been detained over the incident and four were believed to be Iraqi police.
The past week has also seen a surge in deadly attacks on US soldiers - roadside bomb blasts in and near Baghdad have killed nine since last Wednesday. Since the start of the war almost a year ago, 389 US troops have been killed in action in Iraq - 274 of them since Washington declared major combat over on May 1st.
Most of the recent deaths have been caused by low-tech roadside bombs often made from artillery shells crudely wired to a detonator.