BAGHDAD - In a sign of the hair-trigger nerves on the streets of Baghdad, U.S. troops and Iraqi police sometimes mistakenly fire at cars carrying friendly foreign-security contractors, even setting off helter-skelter gunfights.
The latest incident occurred Tuesday afternoon along the lawless road to the airport, the notorious ''ambush alley'' where homemade bombs often explode.
Unmarked vehicles bristling with security guards routinely careen down the road at high speed, carrying foreigners to and from the airport. Driving equally fast are suicide bombers, who hope to ram explosive-laden vehicles into U.S. military convoys.
Late Tuesday, soldiers in a U.S. Humvee spotted what they considered to be a suspicious car. They fired ''six or seven rounds'' at the tires, a security official said, providing information on condition of anonymity. There were no casualties. The vehicle was carrying foreign security guards, whose identities and nationalities weren't released. The U.S. troops quickly realized their mistake.
Police Opened Fire
On Monday, it was a different story -- and a lethal one -- that illustrates the almost-electric tension on Baghdad's streets. When Iraqi police see unmarked cars with gun barrels poking out the windows, they understandably suspect that the cars may be carrying outlaws preparing to attack.
About 10 a.m., a police cruiser spotted a Korean-made white sedan near the Babylon Hotel in central Baghdad on a route often used by Interior Minister Falah Hassan al Naqib. The car reportedly had tinted windows and no license plate.
''The police started to shoot at the car,'' said Mohammed Khalif, a shopkeeper whose grocery is in front of the shootout site and is now marred by a shattered window.
Khalif said the white sedan carried three people. Coming under fire, one occupant broke a window, rolled out of the car and began firing back, Khalif said. The foreigner killed one police officer and shot another in the left shoulder and abdomen, seriously wounding him, Khalif said. An Interior Ministry official confirmed his account. A passerby also was wounded.
Another police cruiser arrived and took the foreigners into custody. They were released later that day.
Inside the car, police ''found AK-47s and grenades,'' Khalif said. ``All my neighbors and I saw their passports. They were foreigners.''
Khalif didn't know the nationalities of the three men, but Al Jazeera television network showed images of a British passport for one of them.
''One of the people at the scene was a British Embassy official,'' said Victoria Whitford, a spokeswoman for the embassy. ``There is a full investigation under way.''
Private-security companies run huge operations in Iraq, employing about 20,000 foreigners, usually retired police or military commandos from the United States, Europe, South Africa, Australia and elsewhere. The employers are largely British and American companies with names such as Blackwater Security, Triple Canopy, Custer Battles and Hart Group.
The private security forces are far better armed and outfitted than the 135,000member police force, and some top security personnel earn as much as $15,000 a month to protect diplomats, guard key installations and ride along with military convoys.
A number of security contractors have been killed.
Some security companies adopt low-key profiles, deploying personnel who ward off kidnappers by discreetly displaying automatic rifles and other arms through car windows.