The battle between Sunni and Shia Muslims for control of Baghdad has already started, say Iraqi political leaders who predict fierce street fighting will break out as each community takes over districts in which it is strongest.
"The fighting will only stop when a new balance of power has emerged," Fuad Hussein, the chief of staff of Massoud Barzani, the Kurdish leader, said. "Sunni and Shia will each take control of their own area." He said sectarian cleansing had already begun.
The Iraqi army is likely to fall apart once inter-communal fighting begins. According to Peter Galbraith, former US diplomat and expert on Iraq, the Iraqi army last summer contained 60 Shia battalions, 45 Sunni battalions, nine Kurdish battalions and one mixed battalion.