There was so little agreement on how to share revenues - with minority Sunnis fearing they would be left out - that the charter even failed to give the government a right to collect taxes.

Some Shiite leaders have publicly said they are prepared to reconcile with the minority Sunnis, who generally prospered under Saddam Hussein's Baathist government.

As the National Assembly met, Iraq's top political figures warned of a sectarian crisis between the majority Shiites and minority Sunnis.

One question is whether to tilt American support more heavily toward the majority Shiite government, rather than the minority Sunnis.

In 1968 the Iraqi constitution established Islam as the official religion of the state as the majority of Iraqis (97%) are Muslim (predominantly Shīʻah but also including minority Sunni).

The party often calls for public demonstrations and political seminars focusing on the issues affecting the majority Shīʻa, who have been ruled by the minority Sunnis for many decades.

Southern Iraq is one of the strongholds of the country's Shiite Muslims, long at odds with the political domination by minority Sunnis.

The challenge in Iraq is that the oil reserves are concentrated in the Shiite south and the Kurdish north, seemingly leaving the minority Sunnis vulnerable.

Fighting was primarily between the majority Shia and the minority Sunni.

Sunni religious scholars are considered highly influential within the country's minority Sunni population.