The US administrator in Iraq is seeking a return of the UN to Iraq, in talks with the secretary general in New York.
Bremer wants the UN to help oversee the handover of power
The move comes amid strong opposition from leaders of Iraq's Shia majority to US plans for the transfer of power to Iraqi hands without direct elections
Diplomats say Paul Bremer will urge Kofi Annan to tell Shias that elections cannot be held before a June deadline.
The UN withdrew all staff from Iraq after a massive car bomb attack on its offices in Baghdad last August.
The meeting comes a day after at least 20 people were killed in the latest suicide bomb attack, outside the US-led coalition's headquarters in Baghdad.
"Once again, it is innocent Iraqis who have been murdered
by these terrorists in a senseless act of violence," Mr
Bremer said in a statement.
"Our determination to work for a stable and democratic future for this country is
The US administrator will be accompanied at the meeting by Adnan Pachachi, the head of the US-appointed Iraqi Governing Council.
Mr Annan has said the UN could help, but only if given a role commensurate with the risks involved.
Mr Bremer's task in seeking UN support was made more difficult by Sunday's suicide blast, which killed at least 20 and injured more than 60.
He said the attack during the morning rush-hour, was timed to kill the maximum number of innocent Iraqis.
The huge blast occurred at about 0800 (0500 GMT) near a heavily fortified entrance to one of Saddam Hussein's former palaces, which now serves as the US administration's civilian and military headquarters.
Most victims are thought to have been Iraqis waiting to meet US officials.
Six Americans, including two soldiers, were reported to be among the injured.
A witness who was driving by said the explosion lifted his car into the air.
The last big car bomb attack in Baghdad was on New Year's Eve, when eight people were killed when a bomb exploded outside a busy restaurant in the city centre.
MAJOR ATTACKS SINCE 1 MAY
18 January 2004: 18 reported killed outside coalition HQ, Baghdad
31 December 2003: Eight killed in Baghdad restaurant blast
14 December: Car bomb at police station kills 17 in Khalidiya, west of Baghdad
12 November: 26 die in suicide attack on Italian police base in Nasiriya
2 November: 16 US soldiers die as Chinook helicopter downed
27 Oct: Red Cross and other buildings in Baghdad bombed, more than 30 killed
29 Aug: Mosque near Najaf bombed, at least 80 dead including Shia Islam's top cleric in Iraq
19 Aug: UN headquarters in Baghdad bombed, 23 killed including head of mission
List covers attacks since US declared war effectively over
On Sunday evening, at least 13 people were injured in a bomb attack in the Shia holy city of Karbala.
The blast happened in a busy street 2km away from the Shrine of Abbas, an important place of pilgrimage.
It was the latest in a series of attacks on Iraq's majority Shia community, but it is not clear who was responsible.
On Saturday, a bomb attack on a patrol north of Baghdad killed three American troops, taking the number killed since the war began in Iraq in March last year to 500.
Stamp of approval
At his meeting in New York, Mr Bremer will try to persuade Mr Annan, to back a US plan to set up an unelected government in Iraq by July.
However, the spiritual leader of Iraqi Shias, Ayatollah Ali al-Sistani, is demanding direct elections first.
The BBC's Susannah Price at the UN says the Americans hope a UN stamp of approval will halt criticism from the Shia community.
But Mr Annan has made it clear that security is a priority and says that he needs greater clarity about what role the UN might be asked to play.