Insurgents vowing total war against Iraq's national elections unleashed a wave of fresh attacks Saturday despite heightened security precautions on the eve of the ballot.

Iraqi officials say a suicide bomber killed eight people outside a military center used by both Iraqi and American forces in the town of Khanaqin near the Iranian border. Today's bomber did not use a car, but walked up to his target and detonated a belt of explosives he was wearing.

Explosions and gunfire were reported near polling stations at a number of locations around the country. Central districts of Baghdad echoed with the sound of heavy machine-gun fire and explosions.

Special security procedures designed to safeguard Sunday's voting are already in effect. All of Iraq's borders have been sealed, and road traffic is restricted. An overnight curfew is in effect and Baghdad's airport is closed.

Iraqis will be choosing a 275-member national assembly and provincial governing councils on Sunday. The assembly is to draft a constitution that will clear the way for elections to choose a permanent government later this year.

Some information for this report provided by AP and Reuters.