TIKRIT, Jan 11: A suicide car bomber killed seven policemen in Saddam Hussein's home town and gunmen shot dead eight people in a minibus south of Baghdad on Tuesday in the latest attacks to threaten Iraq's Jan 30 election.

A group led by Al Qaeda ally Abu Musab al-Zarqawi said it carried out the bombing against what it called "cowardly mercenaries" at police headquarters in Tikrit, a Sunni stronghold in northern Iraq. Eight officers were also wounded.

Repeated militants' 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 explosion, gunmen attacked a minibus travelling through Iraq's notorious "Triangle of Death", massacring 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 Shia 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, and a second bomb killed a policeman, 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 Shias, who expect to emerge dominant after years of oppression.

Zarqawi's group, behind most of the deadliest suicide bombings in Iraq since Saddam's overthrow, has claimed responsibility for both assassinations. Washington is offering $25 million for information leading to the death or capture of Zarqawi, a Jordanian militant whom it regards as its number one enemy in Iraq. -Reuters