In a briefing released on 16 April, the White House said there are about 22 million Iraqis, of which 13 million, equivalent to 60 per cent of the population, are Shias. The UN has consistently reported that the Iraqi population is 27 million. Most independent analysts say that Shias account for about 65 per cent of the population and probably number at least 15 million people.

The wide variance in population estimates could have an impact on plans for the political reconstruction of Iraq. The US, the UK and leading Iraqi opposition groups are calling for a federal system of government based on geography, but it is likely the borders between the three Iraqi zones that may be formed will reflect the distribution of the three principal social groups: Kurds, Sunni Muslims and Shia Muslims. The population balance in the major northern cities Kirkuk and Mosul will also determine whether they are to be part of the northern zone, dominated by Kurdish political groups, or the centre, where the majority of the population is Sunni Arab. Kirkuk, the main oil producing centre in the north, is also claimed by Turkomans, the third largest ethnic group in Iraq after Arabs and Kurds.

The White House briefing estimated that 30,000 Iranians and Iraqis were killed by Iraqi government forces in chemical attacks in 1983-88. Attacks on the Kurds in 1987-88 led to 50,000-100,000 deaths, it said.