Your opinion, please

Okay, here's a report of a car bombing in Baghdad that apparently targeted Iraqi police (killing four of them) that also killed or injured several "innocent bystanders." Is this appropriately called an act of insurgency with "collateral damage," an act of "terrorism," "negligent homicide" or what? If the Soviet Union had occupied the U.S., and Americans were working as police to uphold that occupation, wouldn't an attack on those police by an outraged American be heroic, even though innocent Americans were killed in the process? I dunno, just asking.