Seven people were killed on Sunday in a car bombing in a mainly Shiite area in the Iraqi capital Baghdad, said security officials, dpa reported.
The explosion targeted a prison in the northern district of Kadhmia, leaving 16 wounded.
Iraq has been gripped by sectarian tensions since mass protests started in December in areas populated by the Sunni minority.
The protesters are seeking the repeal of laws they say the Shiite-dominated government of Prime Minister Nuri al-Maliki has used against them.
Hundreds have been killed in recent months in Iraq in a series of retaliatory Sunni-Shiite attacks, raising fears of a sectarian conflict in the country.