Iraqi soldiers inspect a site where car bomb exploded in Hawija
At least five bombings took place across Iraq Tuesday, three of which were suicide car-bomb attacks within minutes of each other.  At least 18 were killed and nearly 40 wounded in the latest violence to shake the country.

Officials say the day of violence began with the detonation of a roadside bomb outside the city of Hawijah, some 240 kilometers north of Baghdad. A short while later, three suicide car-bombers waited in lines at military checkpoints outside the city.
Within minutes of each other, all three had detonated their explosives, in what appears to be a coordinated attack targeting security personnel.
U.S. forces backed by Apache helicopters, then sealed the town, while the casualties were taken to a hospital in the nearby city of Kirkuk.
Later Tuesday morning, another car-bomb attack took place in the capital, Baghdad, also apparently targeting a police patrol.
Witness Khadim Hassan Kazar says a huge piece of the police vehicle flew through the window of his shop.

Mr. Kazar says the policemen parked their car in front of his store before going into a neighbor's shop. A few minutes later the explosion happened. He says he saw the police car completely destroyed and parts of it damaged his shop.

Mr. Kazar adds that he does not think the police were attacked by a suicide bomber.  He thinks the bombers used a remote control device to set off the explosion.
The attack brought to an end a relative lull in violence in the Iraqi capital, following "Operation Lightning," a series of sweeps by Iraqi and U.S. forces designed to locate insurgents hiding in the city.  Officials say roughly 900 were arrested.
Police and military personnel that make up Iraq's fledgling security services are frequently targeted for attack by insurgents.