The bombing took place in western Baghdad, less than 150 yards (meters) from a series of buildings that included offices of Ayad Allawi, Iraq's first post-Saddam prime minister and a secular Shiite, and those of a Sunni lawmaker, Saleh al-Mutlaq, police said. Neither was at the offices at the time of the explosion.
The car bomber turned off the main road and accelerated toward the checkpoint where the morning shift guards were gathered, police said. Police and hospital officials said two guards were killed and 12 injured.
The officials spoke on condition of anonymity because they were not authorized to release details of the attack.