A car bomb hit a police check point in Ameiriya, west Baghdad, wounding three people.
In Kut, a city in Wasit province in the country's south, a suicide bomber killed 10 and wounded 15 others in an attack on a police station.
A car bomber also hit a police check point in Al-Muqdadiya, in Diyala province, killing three and wounding 18.
"The US military and the Iraqi government are adamant that forces aligned to al-Qaeda in Iraq are behind the majority attacks," our correspondent said.
"There are times, as well, when the violence is sectarian. It is very difficult to say that one organisation is behind this flurry of attacks."
Co-ordinated attacks across Iraq. Click on tabs or zoom in for more detail
West of the city of Karbala, a suicide car bomber targeted a police station in Al-Nasser district, killing one person and injuring at least 30, including policemen.
Two car bombs also exploded in Ramadi, west of the capital Baghdad.
"Two terrorists" were killed attempting to rig a car with explosives in the first attack, a police source told Al Jazeera. The second car bomb explosion wounded 12 people.
In the north of the country, one person died and another eight were wounded by a bomb attack in Kirkuk.
In eastern Mosul, a car bomb hit an army check point, injuring three people, including a child.
There are also early reports of an attack in a car park in Basra, southern Iraq.
On Tuesday, a suicide car bomber targeted a police check point in eastern Baquba, the capital of Diyala province.
The attack killed three people and wounded 13 others, mainly police.
It coincided with the arrival of the convoy for Diyala's governor. A bodyguard for the governor was among the dead.
"Certainly, [there has been] a flurry of violent activity in recent hours, coming to that deadline by the United States for its self-declared draw-down of its troops in Iraq,:" our correspondent said.
"Iraq authorities have arrested a large number of people who they say are aligned to al-Qaeda."