A suicide car bomber has crashed his vehicle into a barrier outside a police building in central Iraq, killing at least 13 people and wounding dozens more, officials said.
The blast is the second significant attack in Iraq since the death of Osama bin Laden on Monday at the hands of a US commando team in Pakistan.
Iraqis have been on edge, waiting for al Qaida's branch in Iraq to strike back as a way to demonstrate it is still dangerous. Iraqi security officials have said they are increasing security in the wake of bin Laden's killing.
A police official said the bomber hit when the police were changing shifts in the city of Hillah, about 60 miles south of the capital Baghdad. Most of the dead and wounded were police, he said.
The official put the number of dead at 13 and said 41 people were wounded. Another police official in Hillah confirmed the fatalities, but said 35 were wounded.
In the chaos following attacks in Iraq, such conflicting information is common.
Hillah is a predominantly Shiite city but its proximity to the Triangle of Death - a mainly Sunni area that at one time was one of the most dangerous in the country - has made it a frequent target of Sunni extremists.
There was no immediate claim of responsibility for the blast, but extremists like al Qaida in Iraq have often tried to take out Iraqi forces as a way to undermine security in the country.
On Tuesday, a car bomb tore through a cafe in Baghdad packed with young men watching a football match on TV, killing at least 16 people.
The attack occurred in a Shiite enclave in the former insurgent stronghold of Dora, an area in south-western Baghdad that saw some of the fiercest fighting of the Iraq conflict.