In a memorandum to the UN, Baghdad said it could not guarantee the safety of staff from those two nations because of "popular anger" in the wake of last month's US and UK bombing raids.

"We have accordingly requested that the personnel in question be replaced," the memorandum stated.

The UN is reported to have about 420 humanitarian staff in Iraq, including the three northern Kurdish provinces not directly under Baghdad's control.

John Mills, the spokesman for the UN humanitarian programme in Iraq, did not comment but said the UN was "studying the issue closely".

Fourteen affected

Western diplomats said that 14 British and US nationals would be affected.

The entry visas of 10 - nine Britons and one American - would not be renewed, while four other Britons working for UN contractors would be told to leave Iraq on finishing their assignments.

However, US State Department spokesman James Rubin said that Iraq's deputy permanent representative to the United Nations, Saeed Hasan, had verbally informed UN officials that no workers would be expelled and that the denial of entry visas was "temporary".