Iraqi lawmakers are planning to hold a special parliamentary session on Friday, calling it a defiant stance against terrorism following Thursday's green zone bomb attack.
U.S. and Iraqi officials are investigating how an attacker penetrated the heavy security around Baghdad's green zone and detonated a bomb inside the parliament building, killing eight people and wounding 20 others in a cafeteria. Three lawmakers are believed to be among the dead.
A U.S. military spokesman, Major General William Caldwell said officials suspect the attacker wore a suicide bomb vest.
U.S. and British officials called the attack the work of extremists who oppose Iraq's democracy. Democrats in Washington called the bombing an indication that the war is going badly.
Elsewhere in Baghdad, at least eight people were killed and 22 wounded when a suicide truck bomber blew himself up on a key bridge over the Tigris River (Al-Sarafiyah).
The blast collapsed the steel structure and sent cars plunging into the river during the morning rush hour.
Also Thursday, the U.S. military said one soldier died from small arms fire during a patrol north of Baghdad.
In the northern city of Kirkuk, a bomb attack killed at least six people.