The car bomb exploded at around 8:15 pm (1715 GMT) in the south Baghdad neighbourhood of Dora, an interior ministry official said.
A further 27 people were wounded in the blast.
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Meanwhile, a senior official in the trade ministry narrowly escaped assassination, but was badly wounded, and his driver was shot dead in an attack Tuesday morning, the official said.
A roadside bomb targeting a vehicle carrying Hassan Ismail, a director general in the ministry, exploded in south Baghdad Tuesday morning, at which point a group of gunmen opened fire on Ismail's car.
Another person was also badly wounded.
Also in south Baghdad, an employee of the capital's municipal government, Basma Fattah, was killed by a magnetic "sticky bomb" attached to her car, according to the interior ministry official.
Two other roadside bombs in Baghdad wounded four people in separate incidents.
And in the main northern city of Mosul, police Colonel Eid Names al-Juburi was killed and four of his bodyguards wounded when a bomb targeting his convoy exploded, a police lieutenant said.
Violence levels are dramatically lower than at the peak of Iraq's sectarian bloodshed in 2006 and 2007, but attacks remain common. A total of 211 people were killed in violence in April, official figures showed.
