In addition, the bodies of eight Iraqis who apparently were abducted and killed in captivity, were found in the capital on Monday, police said.
Monday's worst attack occurred in the Saydiya area of southwestern Baghdad when armed men opened fire at two civilian cars, killing three of the municipal workers they were carrying and an Iraqi passerby, said police Captain Talib Thamir.
A car bomber killed two Iraqis and wounded five in an attack on a police patrol in the northeastern neighbourhood of al-Shaab, where fighters had seized and murdered a defence lawyer in Saddam Hussein's trial last week, said police Lieutenant Malik Sultan.
Armed men opened fire on an Iraqi army checkpoint in western Baghdad, killing a soldier and a girl who was standing in front of her nearby house, said police.
In two other attacks in the capital, a drive-by shooting killed one policeman, and two others were wounded by a roadside bomb, the authorities said.
Kurdish politician wounded
In Kirkuk, 290km north of Baghdad, a roadside bomb exploded at 8.30am (0500 GMT) near a car carrying Ibrahim Zangana, a senior member of Iraq's Kurdish Democratic Party, seriously wounding him, killing one of his bodyguards and injuring another one, said Brigadier-General Sarhat Qadir, the commander of Kirkuk's police force.
Another drive-by shooting, this one in Mosul, 360km northwest of Baghdad, killed a policeman.
On Sunday, more than 33 Iraqis died in a swell of violence in Iraq, including 12 labourers, five of them brothers, who were shot dead by armed men at a construction site outside the city of Hilla, about 95km south of Baghdad, police said.
The corpses of eight Iraqis, five men and three women, also were found in three different areas of Baghdad on Monday morning, police said.
All of them apparently had been abducted and tied up or handcuffed before being shot to death.
Fighters also attacked oil pipelines in Iraq's north on Monday for the second time in four days, sparking fires and further setting back the resumption of exports into Turkey, oil officials said.
"Three mortars fell just after 10am on a network of oil and gas pipelines that had already been hit on Thursday by mortar fire," said an official responsible for oil security.
Monday's attack set at least 16
oil pipelines on fire
The explosions set off a fire "and no less than 16 oil pipelines are on fire", around the network, which is 60km west of the northern city of Kirkuk, a technician in charge of repairing oil installations said.
The attack came as the fire sparked by Thursday's attack was brought under control and technical teams were preparing to repair the damage.
According to the technician from the Northern Oil Company (NOC), the damage caused by Thursday's fire will take at least four weeks to repair.
It is only then that the oil can flow again and feed the main export pipeline.