Abdel-Aziz al-Hakim (search), a Shiite Muslim leader who has criticized U.S.-led plans for Iraqi sovereignty, assumed the rotating presidency of the Governing Council (search) on Monday amid discussions about how to select a transitional government.

Al-Hakim succeeded Jalal Talabani (search), leader of a major Kurdish political party who held the post in November. Al-Hakim's turn lasts through December.

The U.S.-appointed Governing Council signed an agreement with Iraq's occupiers Nov. 15 calling for an indirect process of caucuses to select a transitional government that would take power by July.

Key Shiite leaders — including al-Hakim — objected to the plan, saying direct elections are needed.

The council, apparently bending to those demands, set up a committee Sunday to study ways to select a provisional legislature, raising concerns that the transfer of power might not be as easy as hoped.

"Consulting with the Iraqi people is fundamental, and the political process should be built on this principle," al-Hakim said Monday.

The United States, however, wants to stick to the plan agreed to in November.

"The agreement that we and the governing council reached remains in place," State Department spokesman Richard Boucher said Monday. He noted that the plan provides for direct elections to choose the committee for a constitutional convention.

Al-Hakim's spokesman, Adel Abdul-Mahdi, said Governing Council members support the timetable agreed to with the United States but have questions about the method of selecting local councils that will elect a new government.

"The agreement has been in general terms and this all needs detailing," he said. "There need to be clarifications. ... We still don't know 100 percent how this will happen."

The agreement between the council and the U.S. occupation authority calls for choosing a legislature through regional caucuses. That legislature would in turn elect a provisional government to take power by July 1, when the occupation authority would cease to exit.

Last week, Grand Ayatollah Ali al-Husseini al-Sistani (search), Iraq's most influential Shiite leader, demanded the legislature be elected directly.

Al-Hakim, a leader of the Supreme Council for the Islamic Revolution (search), the biggest Shiite political organization, has complained that the council was pressured to approve the plan too quickly and without sufficient deliberations.

Any delay or unraveling of the agreement would be a major setback for the U.S. government and the coalition authority, whose forces face daily attacks by insurgents.

On Sunday, Jalal Eddin al-Sagheer, an official who attended the Governing Council's session, said members agreed that "elections are the best way to precisely know the opinion of the Iraqi people, but there are several difficulties."

"The members of the Governing Council think that the mechanism proposed by the American administration ... will not work as the way to elect the provisional assembly," al-Sagheer said. "An election process would be a much better way than what's on the table."

Yonadam Kanna, a Christian council member, said members think that many city councils and unions — which would be involved in the selection process — do not represent their constituencies.

"They were chosen in a hasty way, and some were imposed by coalition forces," he said.