The rise in violence, which has killed more than 6,200 people this year, has prompted the authorities to appeal for international help in combating militancy ahead of a general election due in April.
The deadliest of Wednesday's violence hit the oil hub of Kirkuk, which has been made fertile ground for insurgents by longstanding Kurdish calls for its inclusion in their autonomous region in the north, despite opposition from Baghdad and non-Kurds among its mixed population.
A car bomb, targeting a police intelligence office in the city center, was followed by a firefight between militants and security forces at the scene.
In all, at least six people were killed and more than 70 wounded, security and medical officials said.
Attacks in Baghdad, Fallujah and near Tikrit, killed three more people, officials said.
The authorities have made some concessions aimed at placating Sunni Arabs, including freeing prisoners and raising the salaries of anti-al-Qaeda fighters, and have also launched security operations against militants.
But daily attacks have shown no sign of abating.
Despite a near-ubiquitous security force presence, attacks have hit targets ranging from cafes and football grounds to military checkpoints and government vehicles.
HH/HH