And Iraqi police clashed with a Shi'ite Muslim militia during a raid on a building in a gun battle that killed four policemen and wounded two.
L. Paul Bremer III, the top administrator in Iraq, has requested that the FBI investigate the slayings of the Americans late Tuesday on a road outside the town of Hillah, 35 miles south of Baghdad, said Dan Senor, spokesman for the US-led coalition. It was not known whether the gunmen were specifically targeting coalition officials. "We're starting to form views on that," Senor said.
It was unclear whether the American civilians were traveling with security. Coalition guidelines discourage the movement of staffers after dark. The roads around Hillah have seen a number of attacks on vehicles, some of them fatal.
An officer with the Polish military, which patrols south-central Iraq, said the gunmen were disguised as policemen and stopped the Americans' car at a checkpoint. The attackers shot the passengers and took the vehicle, Colonel Robert Strzelecki said.
Polish troops later intercepted the car, arrested the five Iraqis in it, and found the bodies inside, said Strzelecki, speaking from the Camp Babylon headquarters of the Polish-led multinational force in Iraq.
Senor said some reported details of the attack were incorrect, but would not elaborate. He did not identify the dead, pending notification of relatives.
The Americans, who were Defense Department employees, were the first US civilians from the Coalition Provisional Authority to be killed in Iraq, Senor said.
An Army colonel working for the coalition was killed Oct. 26, when insurgents fired a barrage of rockets at Baghdad's Rasheed Hotel while Deputy Defense Secretary Paul Wolfowitz was visiting. Fifteen people were wounded, and Wolfowitz escaped unharmed.
Civilian contractors have also been killed. Since the war began, 554 US service members have died in Iraq, 380 of them from hostile action. Since May 1, when President Bush declared major combat operations in Iraq over, 265 US troops have been killed by the insurgency thought to be led by Saddam Hussein loyalists or foreign fighters.
