Ayatollah Hakim was mobbed by followers in Basra
The leader of Iraq's best-known Shia opposition group has told thousands of supporters that Iraqis would not accept a government imposed by foreigners.
Ayatollah Mohammed Baqr al-Hakim was addressing a crowd in the southern city of Basra, after returning from exile in Iran on Saturday.
The 63-year-old cleric was a fierce opponent of Saddam Hussein throughout his 23 years of exile - and many Shias consider him their most important leader.
His movements in Iraq are likely to be closely watched by United States and British officials, who are concerned that he might push for an Islamic state in Iraq.
The ayatollah - who heads the Supreme Council of the
Islamic Revolution in Iraq (Sciri) - has opposed the war against Saddam Hussein and condemned the presence of foreign troops in the country.
"We now have to know our own way to rebuild Iraq, and forget the
past," he told a jubilant followers who had gathered in a stadium in Basra on Saturday.
"We Muslims have to live together... We have to help each other stand together against
"We want an independent government. We refuse imposed government," Ayatollah Hakim went on.
Many of his supporters carried his portrait and chanted their loyalty to him.
"Hakim has had many martyrs in his family," one follower, Mohammad Lamrayani, told Reuters news agency.
"He deserves our welcome after 23 years abroad. It is the right of every Iraqi to come back now after the fall of Saddam Hussein."
The ayatollah had not set foot in his homeland since he went into exile in 1980, at the start of the Iran-Iraq war.
The BBC's Jane Peel says the roads to the stadium were virtually blocked as people rushed to see their spiritual leader.
Iraqi Shias have not seen their spiritual leader for 23 years
But our correspondent adds that, although Basra is dominated by Shias, many are uncomfortable at the idea of an Islamic state.
Some are also wary because of Ayatollah Hakim's Iranian connections.
Ayatollah Hakim's supporters have said he does not favour an Iranian-style Islamic republic for Iraq.
Recently there has been speculation over whether he would continue to head Sciri or hand over the leadership to his younger brother, Abdulaziz Hakim.
He returned to Iraq earlier and, as deputy head of Sciri, has been taking part in talks with US officials on an interim Iraqi authority.
The ayatollah's return comes as the United Nations Security Council debates a draft resolution on post-war Iraq proposed by the United States and Britain.
Several member states have spoken against clauses in the resolution that limit the UN to an advisory and co-ordinating role.
DRAFT RESOLUTION: MAIN POINTS
Lift economic embargo
Phase out oil-for-food programme
New body to administer oil revenues
US and UK to administer Iraq for at least 12 months
France's permanent representative at the UN, Jean-Marc de La Sabliere, said the organisation's role should be enhanced - particularly in the political field.
The Russians say they want to see the return to Baghdad of UN weapons inspectors, and the continuation of the oil-for-food programme under UN supervision.
The current draft resolution aims to end 12 years of sanctions, and gives the British and Americans wide-ranging powers in post-war Iraq.
The 15 members of the security council are holding a weekend retreat with UN Secretary General Kofi Annan, before further formal discussions next week.