Bomb blasts ripped through more than a dozen Iraqi cities on Monday morning, killing 56 people - most of them in the southern city of Kut - in a wave of violence that shattered what had been a relatively peaceful holy month of Ramadan, AP has reported.

The violence struck from the northern city of Kirkuk to the capital of Baghdad to the southern Shi'ite cities of Najaf, Kut and Karbala, and emphasised the persistent ability of insurgents to wreak havoc at a time when Iraqi officials are weighing whether they are able to protect the country without the assistance of American troops.

The blasts were coordinated to go off in the morning and included a combination of parked car bombs, roadside bombs and a suicide bomber driving a vehicle that rammed into a police station.

The scope of the violence - seven explosions went off in different towns in Diyala province alone - emphasised the still dangerous ability of insurgents to co-ordinate and carry out attacks despite repeated crackdowns by Iraqi and US forces.

The worst violence came in the southern city of Kut, 160km southeast of Baghdad, where twin explosions went off as construction workers were gathered in a market selling generators and other appliances.

The first bomb went off in a freezer used to keep drinks cold, the police said. Then as rescuers and onlookers gathered, a parked car bomb exploded.

The head of the provincial security committee in Wasit province, Shamil Mansour, said 35 people were killed; another official put the number of injured at 64.

Mansour blamed the security breach on a political system that appoints people to government offices based on their sectarian and political affiliation inside of their ability or experience.

In Diyala province, seven bombs went off in the capital of Baquba and towns nearby, said Faris al-Azawi, the spokesperson for the Diyala health directorate. Five soldiers were killed in Baquba while six people were killed in other attacks around the province.

Just outside the holy city of Najaf, a suicide car bomber ploughed his vehicle into a checkpoint outside a police building.

Police opened fire on the vehicle when the driver refused to stop at the checkpoint, and then the vehicle exploded. Four people were killed and 32 injured; among the dead were two policemen and two civilians.

There were also reports that outside Karbala, a parked car bomb targeting a police station killed three policemen and injured 14 others.

In the northern city of Tikrit, two men wearing explosives belts, reportedly drove into a heavily guarded government compound wearing military uniforms which helped them avoid notice by the guards.

The men parked their vehicle and then walked to a building housing the anti-terrorism police. When the men approached the building, the guards ordered them to stop and then opened fire. One bomber was immediately killed but the other managed to get inside the building before blowing himself up and killed three people, al-Asi said. Ten people were also injured in the attack.

In the northern city of Kirkuk, a car bomb exploded next to a police patrol on Monday morning, injuring four police officers. Then about thirty minutes later one person was killed when a motorcycle with a bomb planted inside it exploded.

Late on Sunday, four bombs also blew up near a Syrian Orthodox Church in Kirkuk. No one was injured in the attack but the walls of the church were damaged.

In Baghdad, a parked car bomb exploded near a convoy carrying officials from the Ministry of Higher Education. Eight people were wounded. The minister was not inside the convoy.

The blasts were the first major act of violence since Iraq's political leaders earlier this month announced that they would begin negotiations with the US over whether to keep a small number of American forces in the country past December 31. The last such single large bombing came on July 5, when 37 people died during an explosion in Taji, north of Baghdad.

There was no immediate claim of responsibility for Monday's attacks.