The election mission, which is due to get under way within days, was the focus of talks earlier this week between UN Secretary-General Kofi Annan and U.S. President George W. Bush.
One of Annan's top aides, Lakhdar Brahimi, has also recently visited the White House twice to confer on Iraq.
Annan has declined to speculate on what further role the UN can play beyond in Iraq resolving the elections dispute. But he has made it clear he expects the Coalition Provisional Authority (CPA) to accept the recommendations of the UN's elections mission.
In comments on 4 February, Annan referred to commitments made at a 19 January meeting with CPA leaders at UN headquarters.
"As to whether they would accept my conclusions or not, when we met in this building, both parties -- the CPA and the [Iraqi] Governing Council -- indicated they will. Of course, that was before they see the [UN] report. I hope once the report is on the table the attitude will be the same," Annan said.
A UN official and a U.S. diplomat both told RFE/RL that there was no formal agreement at the January meeting that the CPA would accept the recommendations of a UN elections mission. But the UN official said there was an understanding that the CPA would abide by the report's finding.
The White House and CPA chief L. Paul Bremer this week both said the United States is prepared to consider "refinements" to its original plan for a provisional government.
Washington prefers a system of regional caucuses to select leaders for a transitional assembly, which would then choose the members of an interim government to take over on 1 July. But Iraqi Shi'a leaders have been demanding direct elections. U.S. officials say such elections are unrealistic given the short timeframe.
UN officials have declined to provide much advance information about their assessment team, citing security concerns. It is expected to begin work within days and report back to UN headquarters before the end of the month.
The UN mission is going to meet with all major Iraqi groups and try to determine if elections are possible by the end of May. Bremer said yesterday that if elections are found not to be possible, the mission has been asked to recommend whether the 15 November agreement on transition can be modified to select a transitional national legislature by the end of May.
Annan has stressed the importance of international support in guiding Iraq's democratic transformation. But he has also said the UN must have a substantial political role before he would consider sending staff back to the country.
The secretary-general removed UN staff from Iraq after the August 2003 attack on UN headquarters in Baghdad. UN envoy Sergio Vieira de Mello, who had been working closely with Bremer, was killed in the attack, along with more than 20 others.
It is crucial for the transition to be seen as legitimate in the eyes of Iraqis and their Arab neighbors, says Clovis Maksoud, a Middle East expert at the Washington-based American University.
Maksoud, a former UN representative for the League of Arab States, told a news conference yesterday that places Annan in a difficult spot.
He says Annan must take into account both the will of the UN membership, Iraqis and the world's lone superpower, the U.S. "It is the responsibility of the United Nations to promulgate a policy of action in Iraq that satisfies both [Iraqis and Arabs] and that can be done through the United Nations, assuming full authority through a mandate from the Security Council, to supervise the transitional phase which would end the occupation and provide the outcome to be a legitimate government," Maksoud said.
There have been conflicting signals from Washington about its support for a lead UN role in Iraq. After the Bush-Annan meeting, the Associated Press quoted unnamed Bush administration officials as saying that the United States is looking to the UN to help end the dispute in Iraq over elections but not to assume control of the process.
On the other hand, "The New York Times" quoted U.S. officials as saying it is possible for the UN to take the lead role in guiding the Iraqi political process after the return of self-rule.
The trips by Lakhdar Brahimi to Washington are believed to have been sought by officials who hope he can assume the same post in Iraq that he did in Afghanistan after the ouster of the Taliban. Brahimi has repeatedly refused to consider such a role.