Voting for Iraqi expatriates begins today in the wake of another bloody day in the Gulf state yesterday.
A total of 20 people were killed as result of anti-election attacks in Iraq just three days ahead of a poll likely to show lower-than-hoped-for participation levels.
A car bomb exploded today close to a police station in southern Baghdad, killing four Iraqi civilians.
A US soldier was among those killed as militants across the country attacked police stations and schools designated as polling stations on Sunday.
Yesterday's attacks, including the execution of four Iraqi National Guards, came as US investigators investigated a helicopter crash that killed 31 US troops on Wednesday.
President Bush has urged Iraqis to "defy the terrorists" and vote in the country's first election since an US-led invasion toppled Saddam Hussein in April 2003.
But the Islamist militant Army of Ansar al-Sunna issued a "final warning" to people to stay away from the polls, saying anyone who voted would be marked for death, either during or after the election.
"Those who don't pay heed will have only themselves to blame," the group said in a statement on an Islamist website.
Another faction led by al-Qaeda's leader in Iraq, Abu Musab al-Zarqawi, which has led the bloodiest attacks in the electoral countdown, has declared "holy war" on the poll.
Yesterday, gunmen abducted and executed four National Guards in the western city of Ramadi. Notes were found pinned on the four bodies warning against collaboration with US troops.
In Samarra, north of Baghdad, a roadside bomb killed three civilians and another explosion near an Iraqi army patrol killed a soldier and two bystanders.
Insurgents also blew up a school administration building designated as a polling station in Samarra after ordering workers out. At least five other sites scheduled for voting were bombed in neighbouring towns.