The UN mandate for US-led forces in Iraq expires at the end of the year
Iraq's cabinet is demanding changes to a draft agreement with Washington that would allow US forces to stay until 2011, a government spokesman has said.
"The cabinet have agreed that necessary amendments to the pact could make it nationally accepted," Ali Dabbagh said, without specifying the changes.
The draft was presented last week after months of painstaking US-Iraq talks.
US officials have not said if they are willing to renegotiate the Status of Forces Agreement (SOFA).
The draft agreement calls for a drawdown of US combat forces from Iraq by the end of 2011 and includes US concessions on immunity for US troops who break Iraqi law.
The US and Iraqi governments had previously said the pact was final and could not be amended - only accepted or rejected by the Iraqi parliament.
But Mr Dabbagh said ministers would meet over the coming days to "give their opinions and consult and provide the amendments suggested" before submitting the amended draft to the US negotiating team.
Mr Dabbagh issued a statement asking "everyone to view the agreement objectively and responsibly and to consider the public interest".
The cabinet must approve the draft before it can be sent to parliament for a vote.
Apart from the two main Kurdish parties, political leaders have so far withheld their support for the deal.
Thousands protested on Saturday against the US presence in Iraq
The draft has also been strongly opposed by the faction led by radical Shia cleric Moqtada Sadr, who brought thousands of supporters on to the streets of Baghdad on Saturday in protest.
Immunity for US military personnel and contractors is thought to be one of the key sticking points, the BBC's Jim Muir reports from Baghdad.
The pact is said to grant Iraqi judicial authorities limited ability to try US troops and contractors for major crimes committed off-duty or off-base - and only then if a joint US-Iraqi committee agrees.
Earlier on Tuesday, the US military chief in Iraq, Adm Michael Mullen, warned that Iraq risked security losses of "significant consequence" unless it approved the deal.
Adm Mullen told AFP that Iraqi forces would "not be ready to provide for their security" before the expiration of the current UN mandate for US-led coalition forces at the end of this year.
If a deal is not reached by that point, there will be no legal basis for the US-led mission to remain in Iraq.
"It's time for the Iraqis to make a decision," Adm Mullen said.
About 144,000 of the 152,000 foreign troops deployed in Iraq are US military personnel.