Even as US and British leaders on Tuesday endorsed a 'vital role' for the United Nations in Iraq after the end of the war, the world body is seemingly unsure what that role could possibly be.

"We welcome any indications of an important role for the UN in post-conflict Iraq," Fred Eckhard, spokesman for the Secretary General, told journalists in New York on Tuesday.

"I don't think we have a clearer sense of what that role might be," Eckhard said,

"We would expect the Security Council to define whatever role -- beyond the humanitarian one that might already be included in the mandates of our specialized agencies -- that we might have in Iraq after the conflict," he said during a press conference.

Secretary General Kofi Annan has also wanted a role for the UN in post-conflict Iraq, saying that the legitimacy of any new government that might be set up in Baghdad would be enhanced if it had the blessing of the international community.

Annan on Tuesday named a special adviser, Rafeeuddin Ahmed, to help him draw up a framework for UN involvement and also prepared to visit key players in the crisis.

Ahmed, a Pakistani, has been assisting the UN informally since February in thinking about possible UN involvement in a post-war Iraq.

Annan, who later this week will travel to London, Berlin, Paris and Moscow to discuss Iraq and a possible UN role with British, German, French and Russian leaders, met with members of the Security Council on Tuesday

The US had earlier said it would not like the UN to get involved in anything beyond humanitarian work in Iraq.

In reply to a question whether the 'vital role' might refer only to humanitarian role, Eckhard said the UN would not be disappointed if was so.

"But we think that it would be unwise and we are waiting for marching orders from the Council," he said.

Eckhard drew the attention of journalists to the UN's experience in the administration of post-conflict situations like in Afghanistan, but said that much depended on what the Security Council wants it to do in Iraq.

Eckhard parried a direct reply on whether Annan would propose a specific role for the UN in his talks with world leaders.