The attack came a day after suicide bombers killed more than 70 worshippers at a Shi'ite mosque in the Iraqi capital.
No one has claimed responsibility for either bombing.
The attack in Baghdad came after the Interior Ministry issued a warning that it had received intelligence that insurgents were preparing to detonate several bombs in Baghdad.
The authorities warned that some car bombing were possibly being planned for southern provinces.
RFE/RL Iraq Report
SUBSCRIBE For weekly news and analysis on Iraq by e-mail, subscribe to "RFE/RL Iraq Report."