US Secretary of State Colin Powell has insisted that US forces in Iraq will remain under American control after the 30 June handover of sovereignty.
Mr Powell seemed to contradict an earlier statement by the UK leader
Mr Powell said that while the Americans would consult the Iraqi authorities, US military units would do whatever was necessary to protect themselves.
This seemed to contradict an earlier statement by the UK prime minister.
Tony Blair said the new Iraqi government would have "final political control" on military operations.
Diplomats from the 15 UN Security Council nations will meet in New York on Wednesday for informal talks on the resolution.
BBC News Online world affairs correspondent Paul Reynolds says the apparent differences between Washington and London in part reflect the differing political needs in each capital.
The British want to boost the status of the interim government, while the Americans want to emphasise the right of the multinational force to remain under its own command.
The exact policy is due to be addressed in an exchange of letters between the interim government and the coalition which will lay out the terms under which the troops will stay, our correspondent adds.
Security and sovereignty
The BBC's Justin Webb in Washington says the comments by Mr Blair and Mr Powell show that it is still not clear what degree of sovereignty the new Iraqi government will have.
Asked if the new government could veto a US operation, Mr Powell told a news conference with Belgian Foreign Minister Louis Michel: "Obviously, we would take into account whatever they might say at a political and military level."
HANDOVER: KEY DATES
24 May: US and UK table draft resolution
End of May: UN envoy Lakhdar Brahimi to name Iraqi interim government
Early June: Detailed agreement on control of foreign troops in Iraq
Early June: US, UK hope UN resolution can be adopted - maybe by D-Day celebrations on 6 June, or by the G8 Summit on 8 June
30 June: Handover from Coalition Provisional Authority to interim government
But he said that ultimately, "US forces remain under US command and will do what is necessary to protect themselves".
The text of the draft resolution says that the interim Iraqi government will have sovereignty, but limited control over coalition military operations.
The resolution does not specify that the troops will leave Iraq if the new government asks them to.
Later on Tuesday night, Mr Powell said he was confident that US troops would be able to co-ordinate security needs with a future Iraqi government.
"We have a great deal of experience in these kinds of arrangements... " he said, and added: "I'm quite confident we will be able to work out arrangements that will be satisfactory to all."
Mr Blair on Tuesday stressed that "the final political control remains with the Iraqi government".
"That's what the transfer of sovereignty means," he added.
Asked whether Iraqi ministers would be able to veto military action such as a renewed assault on the restive Iraqi city of Falluja, Mr Blair said any action would need "the consent of the Iraqi government".
He said it would be up to the Iraqi government and its people to decide "whether the troops stay or not".
Concerns on resolution
Earlier, France - one of the five veto-wielding members at the UN Security Council - has expressed reservations about the draft resolution released on Monday.
Russia, another country which has the power to block the resolution, said the draft raised a number of questions and needs changes.
Iraq's Governing Council has said the draft resolution, while positive, has fallen short of their expectations and the final version must guarantee Iraq's right to ask foreign troops to leave.
Our Washington correspondent says that whatever the precise powers the new Iraqi leadership will be granted, the White House is hoping to be at a point very soon when the UN special envoy to Iraq can announce the names of people taking over the key posts.
US reports quoting government sources said Hussain al-Shahristani, a Shia nuclear scientist once imprisoned by Saddam Hussein, was likely to named prime minister.
There has also been a mixed reaction to the US president's keynote speech on Monday in which he defended his vision for Iraq.
Mr Bush said he was taking five "specific steps" to help Iraq achieve freedom and democracy.
He said that the UN would have an important role, but stressed that the US would keep its troops in Iraq at the current level as long as necessary because of the continuing unrest.
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