Political leaders representing Iraq's ethnic and religious groups remain at odds over key provisions of a new constitution, despite Monday's deadline for completion of a draft document.

Friday prayers brought calls from Sunni Arab clerics for followers to reject federalism and vote against a constitution containing provisions that divide the country.

On Thursday, Abdul-Aziz al-Hakim, the leader of Iraq's largest Shi'ite party, the Supreme Council for Islamic Revolution announced his support for a federal region in central and southern Iraq.

Iraq's Kurds also favor a federal structure that will protect their autonomous status in the country's north.

The draft is to be submitted to Iraq's National Assembly Monday for debate before an October referendum.

In other developments, a roadside bomb attack early Friday killed an American soldier who was on patrol in Tikrit, north of Baghdad.

Some information for this report provided by AFP and AP.