Iraq's interim government is enforcing a number of security measures ahead of this Sunday's election.
It is the first election since the downfall of Saddam Hussein.
The country's land borders have been sealed, curfews are being introduced and Baghdad airport will be closed from tomorrow.
Meanwhile, Iraqis living abroad have been casting their votes ahead of Sunday's national election.
Expatriates in 14 countries around the world are eligible to cast their ballots, but it looks likely that fewer people will do so than had been expected.
An estimated 1.2 million exiled Iraqis could take part, but only 280,000 have registered for the poll.
Election officials say that many Iraqis living abroad have not done so for fear of persecution against themselves and members of their families still living in Iraq.
Inside Iraq, the security forces have begun distributing ballot boxes. The location of polling stations is being kept secret until the last minute to prevent attacks by insurgents.
All security at the stations will be handled by Iraqis, with US forces taking a back seat to try to reduce tensions.
A US military spokesman, Brigadier Jeffery Hammon, said he remained optimistic in spite of the threat of attacks.
