Elsewhere in and around the capital, gun attacks and explosions killed three people, officials said.
In Mosul, one of the most violent areas of the country, twin car bombs set off by suicide attackers killed 21 people, including 14 soldiers and policemen, in the west of the city.
Also in Nineveh province, of which Mosul is the capital, two other attacks left two people dead.
No group immediately claimed responsibility, but Sunni militants including those linked to the jihadist Islamic State of Iraq and the Levant often set off coordinated bombings across Baghdad and other major cities, ostensibly in a bid to sow instability.
Also in north Iraq, a series of 11 bombings in the ethnically mixed town of Tuz Khurmatu killed five people, four of them members of the same family, and wounded 11.
The blasts targeted homes belonging to ethnic Turkmen.
