Elsewhere in the capital, a roadside bomb detonated as a police patrol passed, wounding nine people, six of them civilians.
A third attack, thought to have targeted government vehicles, left two people injured in the southeastern neighbourhood of al-Ghadir.
Violence in Iraq has fallen to its lowest level since 2004, but last Monday at least 32 people were killed when three suicide bombers targeted a Shia pilgrimage in the Iraqi capital.
On the political front, the Iraqi parliament remained deadlocked over a law on local elections.
A special session called in an attempt to resolve a dispute over the northern city of Kirkuk was postponed, after politicians failed to reach agreement once again.
A senior parliamentary official said politicians were leaning towards approving the UN proposal, and would wait for a committee to submit its recommendations at the end of the year.
Sunni Arabs and Turkomen in Kirkuk are seeking international protection, the official said.
Thousands of Arabs and Turkomen staged a rally in Hawija, a northern city, on Saturday to protest against the move to incorporate Kirkuk region into the autonomous Kurdish region.
Residents of Kirkuk fear that if politicians fail to reach agreement, tension could rise in the city, where a suicide bomb attack killed 25 people last week during a Kurdish protest.
Underscoring the importance of the Kirkuk issue, George Bush, the US president, telephoned Iraq's parliamentary speaker and a vice-president to urge a resolution, according to statements Sunday from their offices.