Nine people were also wounded when a car bomb exploded in a market in the Shaab suburb of northeast Baghdad, the official said.
In Baquba, north of the capital, a six-year-old boy was injured when the car he was travelling in was hit by a roadside bomb, a local security official said.
Two soldiers were also wounded by a roadside bomb in the town of Abara outside Baquba, the capital of the province of Diyala, which remains one of the most dangerous areas in the country.
Three traffic police were wounded by a bomb planted on the road to the Jordanian border in Saqlawiya district, west of Baghdad, a local police official said.
Despite an overall drop in violence in Iraq in recent months, attacks on security forces and civilians remain common in Baghdad, Mosul and in the ethnically divided northern oil-rich city of Kirkuk.