The head of the Iraqi Governing Council has said the US plan for handing over power to Iraqis may be amended.
Talabani appeared to support Sistani's proposed changes
Jalal Talabani made the comments after meeting one of Iraq's most senior Shia religious leaders, Grand Ayatollah Ali Husseini al-Sistani.
Ayatollah Sistani had been pressing for official recognition of Islam and for more direct elections.
The meeting came as the Pentagon announced plans to send about 3,000 additional US marines to Iraq.
Mr Talabani, a Sunni Kurd who chairs the Governing Council this month, told reporters the ayatollah's views were "logical and reasonable" after meeting him on Thursday.
He said the cleric wanted direct elections for the transitional councils that are to draft the country's new constitution and choose transitional leaders.
The US plan calls for appointed bodies - rather than the Iraqi public - to choose the transitional councils.
Shias have been left out of power for generations
Mr Talabani appeared to back the Shia leader's call for direct elections, saying, "He believes, correctly, that this is democracy."
He said he would discuss the proposals with the US and the rest of the Governing Council.
Shias are believed to make up 60% or more of Iraq's population, but have traditionally had little political power.
The talks between Mr Talabani and Ayatollah Sistani came as the US announced changes to next year's massive rotation of US forces in Iraq.
The announcement comes amid continuing attacks on US-led coalition troops, but the Pentagon denies it is in response to a worsening security situation.
In the latest attack on Wednesday, a rocket or mortar round was fired at the Italian embassy in the capital, Baghdad, but no one was injured.
The missile hit the second floor, causing structural damage, Italian news services reported.
Other countries have been reluctant to contribute troops
The attack comes two weeks after the loss of 19 Italian soldiers in a suicide bomb attack in the southern city of Nasiriya.
Earlier this month, the Pentagon said it aimed to see the number of troops serving in Iraq fall from the current 130,000 to 105,000 by May 2004.
The extra deployment of marines will mean the reduction is smaller.
Three additional marine corps battalions have been earmarked to serve in Iraq.
Each battalion consists of about 900 marines, and support staff will add to the total. Pentagon officials say the exact make-up of the extra deployment has not yet been finally settled.
"The exact number, where they are going to come from, the reserve-active duty mix, the timeline of deploying them - all of that is to be determined," said Marine Corps spokesman Major Douglas Powell.
The deployment will form part of the huge force rotation, when 100,000 replacement troops will take the places of those currently serving in Iraq.
This is estimated to be the largest movement of US troops of its kind since World War II.
Pentagon officials deny the extra troops have been fielded in response to the unabating onslaught of attacks on coalition targets - and increasingly against Iraqis seen to be collaborating with the occupiers - in Iraq.
"This is not 'the sky is falling'," one defence official told Reuters news agency.
"This is more planning. This is a minor tweak in the plan."
The US administration has always insisted it would be ready to increase the troop presence in Iraq if necessary.
Little help for US
The deployment of additional marines reflects the difficulties the United States has had persuading allies to join the post-war operation in Iraq.
Turkey dropped plans to contribute 10,000 troops to the peacekeeping effort earlier this month.
South Korea may contribute 3,000 troops. However, this is fewer than the US requested - and in the face of deep domestic hostility, Seoul may downgrade them from combat troops to support staff.
Japan has committed troops - but only 1,000, and not until some time in 2004.