A car bomb struck police headquarters in Tikrit, a Sunni Muslim stronghold 175 kilometres north of Baghdad. Authorities said eight officers were also wounded.

Repeated guerrilla attacks on the Iraqi police and soldiers who will be tasked with protecting polling stations have deepened fears of major bloodletting on the day Iraqis vote in the controversial election.

Shortly after the blast, gunmen attacked a minibus travelling through Iraq's notorious "Triangle of Death," killing eight people and kidnapping three, police in the area said.

Police said it was not immediately clear who was in the vehicle. Sunni insurgents regularly target Iraq security forces and Shi'ite pilgrims in the lawless zone of dusty towns, which is regarded as one of the most dangerous parts of Iraq.

Cars are routinely stopped by insurgents setting up illegal checkpoints to search for those they regard as collaborators with US-led troops and the American-backed interim government.

In the northern Iraqi city of Samarra, a roadside bomb against a joint US-Iraqi convoy killed two Iraqi National Guards, police said.

Leading Sunni Arab political parties say they will boycott the election because violence in the Sunni heartland will scare away voters and skew the results in favour of majority Shi'ites, who expect to emerge dominant after years of oppression.

Insurgents have killed more than 100 Iraqis in the past week alone, mostly security force members they regard as collaborators with foreign occupiers.

In fact, the new spat of violence came on the same day as the alleged ringleader of the Abu Ghraib prison scandal went on trial with witnesses telling a military court they watched him punch an Iraqi inmate in the face and saw him laugh while forcing prisoners to pose naked.

Specialist Charles Graner Jr is the first soldier accused in the scandal to go on trial. His case is an important test of an argument put forth by defence attorneys that the soldiers were ordered to soften up detainees for interrogators and had no choice but to obey. A military guard testified on Monday that he saw Graner punch an Iraqi detainee in the face a moment after a notorious photo was taken at Abu Ghraib prison.

Graner, a 36-year-old former prison guard from Uniontown, Pennsylvania, is charged with conspiracy to maltreat Iraqi detainees, assault, dereliction of duty and committing indecent acts.

An all-male jury of four Army officers and six senior enlisted men will decide his fate in what is expected to be a weeklong trial. If convicted on all counts, he faces up to 17 and a half years in a military prison.

(China Daily January 12, 2005)