And in Sadr City, another Shiite district in the north of the capital, a booby-trapped motorcycle exploded near a group of day labourers waiting to pick up work, killing seven and wounding 20 others.
A short time later, twin roadside bombs detonated near the district's main hospital as victims were being ferried in, killing two more people and wounding 15 an official said.
The United States and United Nations have urged calm amid a political standoff sparked by the authorities' decision to issue an arrest warrant for Sunni vice-president Tariq al-Hashemi on terror charges.
Hashemi, who is holed up in the northern autonomous Kurdish region, denies the charges and his Iraqiya party has boycotted cabinet and stayed away when parliament re-opened on Tuesday.
Prime Minister Nuri al-Maliki on Wednesday backed off threats to fire ministers from the Sunni-backed Iraqiya bloc who have boycotted cabinet, the latest in an apparent toning down of the crisis.
Sunni Deputy Prime Minister Saleh al-Mutlak, also a member of Iraqiya, has decried Maliki as a dictator "worse than Saddam Hussein", and the premier has called for him to be sacked. MPs were due to have considered that request on Tuesday, but the motion was not discussed or voted on.
Violence is down nationwide since its peak in 2006 and 2007, but attacks remain common, especially in Baghdad. A total of 155 people were killed as a result of violence in December, according to official figures.