There was no immediate claim of responsibility for the attack, which also wounded one person in the Baladiyat district of eastern Baghdad.
Iraq is facing a major security threat from Islamic State, an ultra-hardline extremist group which controls a third of the country as well as parts of neighbouring Syria.
The presence of the insurgents has exacerbated a sectarian conflict in the major oil producer and OPEC member with a Shia-led government.
In the Abu Dsheer district in southern Baghdad, at least two people were killed and seven wounded when a bomb exploded near a crowded market, police and medical sources said.
Efforts to contain Islamic State are currently focused on the Sunni heartland Anbar province in the west of the country and the town of Baiji in the north, near Iraq's biggest refinery.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ