As the US struggles to encourage the emergence of a new Iraqi leadership to take over after a period of military rule, BBC News Online looks at some of the likely key figures.
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Ahmed Chalabi, INC:
Leader of the Iraqi National Congress (INC), a fractious opposition group in exile that the US and UK have backed since after the 1991 Gulf War.
Mr Chalabi is a US Defense Department favourite
He has the support of Washington hawks and the Department of Defense, and was moved into Iraq last week by the US military.
The US State Department is extremely distrustful of Mr Chalabi. His critics accuse him of corrupt business dealings and point out that he has no backing inside Iraq, which he left in the 1950s.
Analysts say that as a Shia, even a secular Shia, he arouses the mistrust of the former Sunni ruling class of Iraq.
Iyad Alawi, INA:
The Iraqi National Accord was set up in 1990 by the Iraqi-born Shia Iyad Alawi.
The INA consists mainly of military and security defectors and for many years supported the idea that the US should try to foster a coup from within the Iraqi army.
Some estimates put the number of former Iraqi officers living in exile in Europe and America at 1,000.
Reports say the group has received financial support from US, Saudi Arabia, Kuwait and Britain.
The failure of attempts to engender a coup in Iraq have meant that the INA has been largely overshadowed by the INC.
Ayatollah Muhammad Baqr al-Hakim, Sciri:
The ayatollah runs the Tehran-based Supreme Council for the Islamic Revolution in Iraq (Sciri) and has a 10,000-strong militia under his command.
Ayatollah Muhammad Baqr al-Hakim has refused to send representatives to the first US-sponsored meeting
He has supporters in Iraq, but the Iranian connection makes the US - and some Iraqis - wary of him. Sciri boycotted the first US-sponsored meeting of Iraqi factions on 15 April.
Mr Pachachi is a former Iraqi foreign minister. The 80-year-old Sunni has been courted by the Americans and he is well connected in the Gulf - he is now based in Abu Dhabi.
He is a nationalist with a secular liberal outlook. Some see him, because of his age, as a possible caretaker leader. He is believed to be favoured by the US State Department.
Jalal Talabani and Massoud Barzani:
The leaders of the two Kurdish factions in northern Iraq have a firm base among their own people but would be unlikely contenders for national power.
In an Iraq with a devolved Kurdish region, they would be expected to lead some kind of power-sharing government despite years of often violent rivalry.
A prominent Iraqi general who defected to the West, Mr Khazraji is sometimes mentioned as a possible successor to Saddam Hussein - a leader with strong military connections who could take on the role of "strongman".
Delegates at a meeting on Iraqi leadership sponsored by the US in mid-April
The CIA is reported to have helped him escape to the Gulf from house arrest in Denmark, where prosecutors were investigating his alleged role in gas attacks on the Iraqi Kurds.
His once close connections with the old regime may make him unacceptable to Iraqis as a whole.
The Hashemites, a family that traces its descent from the Prophet Muhammad, rule Jordan and ruled Iraq before the monarchy was deposed by a military coup in 1958.
Prince Hassan of Jordan, a Hashemite, is seeking a role as a UN ambassador to Iraq
Prince Raad, who describes himself as the "head of the Royal House of Iraq", openly backed the US campaign in Iraq.
Prince Hassan of Jordan is seen as an outside candidate among the royalists, and is related to two former kings of Iraq, King Faisal I and King Faisal II. He is pressing for a role as a UN ambassador to Iraq.
A third royalist contender might be the INC spokesman Sherif Ali bin Hussein, the leader of the Constitutional Monarchy Movement.
The number of Iraqis who actually support the return of the monarchy is probably very few, but there is some speculation that the Hashemites might help bridge sectarian divisions - they are Sunnis but revered by many Shia as descendants of the Prophet Muhammad.
In the absence of a candidate with impeccable credentials, a Hamid Karzai for Iraq, the US may try to build up a collective leadership - one which would represent Iraq's mosaic of different communities and command enough confidence to return the country to some sort of normality ahead of elections in a few years' time.
While the US struggles with trying to draw out a new Iraqi leadership, local and tribal leaders are emerging to further muddy the waters.
In the south of the country, tribal Sheikhs are reported to have pre-empted the process by establishing local councils of their own, free of Baath party officials.
In the southern city of Basra, British forces have stirred up protest by appointing a former general and Baath Party official, who also claims to be an important tribal leader, to head a new local council. Further north, in the town of Kut, the US military is trying to remove a Shia cleric who, apparently with Iranian backing, has installed himself as the new mayor. In the capital Baghdad different figures are emerging suburb by suburb in an effort to end disorder and establish some form of local control.
The outbreak of infighting among Shia factions in the holy city of Najaf may also be a worrying sign of the difficulties ahead - and new leaders might yet emerge from this fighting.
Shias in Karbala turned out to demonstrate unity the day after the murder of a leading cleric
One Shia cleric was murdered in Najaf days after his return from exile in Britain. The house of another leading cleric has been surrounded by armed men demanding that he leave Iraq.
The violence appears to be led by Jamaat al-Sadr al-Thani, a Shia faction led by Moqtada Sadr, the son of a Shia cleric murdered by the old regime, Muhammad Sadiq al-Sadr.
The name of the murdered cleric clearly has powerful resonances - the Shia district of Baghdad, Saddam City, has already been renamed Sadr City.