Iraqi policemen secure the area of a suicide car bomb attack together with US soldiers in Baghdad, Iraq

Insurgents in Iraq killed at least 11 people Monday, including a U.S. soldier, in a series of bombings and shootings five days before a referendum on the country's proposed new constitution.

The soldier died in a suicide bombing at a checkpoint outside Baghdad's heavily fortified Green Zone. Elsewhere in the capital, gunmen opened fire on a convoy carrying delegates from the Arab League. There were reports of casualties among guards assigned to the convoy.

The attacks came as negotiators from Shi'ite and Kurdish factions that dominate parliament continued talks aimed at winning last-minute Sunni Arab backing for the draft constitution. U.S. Ambassador Zalmay Khalilzad was also attending the Baghdad talks.

Participants say the negotiators remain far apart on several key issues, including federalism provisions that Sunnis Arabs fear will give too much economic and political power to Iraq's Shi'ites and Kurds.

Some information for this report provided by AP and AFP.