In the south Baghdad neighbourhood of Dora, a policeman was killed and three of his colleagues wounded when a roadside bomb exploded, an interior ministry official said.
In the nearby district of Saidiyah, one civilian was killed and three others injured by a magnetic "sticky bomb" affixed to a car, the official added, speaking on condition of anonymity.
Fourteen people were also wounded -- eight of them policemen -- when two roadside bombs exploded near a mobile phone shop in the west Baghdad neighbourhood of Ghazaliyah.
And in the main northern city of Mosul, one policeman was killed and another wounded by a roadside bomb, a police official said. A young child was also among the injured.
US and Iraqi officials have warned of the dangers of an upsurge in violence as negotiations on forming a new governing coalition have dragged on, giving insurgent groups an opportunity to further destabilise the country.
More than four months after a March 7 general election which gave no single bloc an overall parliamentary majority, the two lists which won most seats are still bickering over who should be the next prime minister.