"The UN refugee agency is very concerned about the general lawlessness that is apparent in part of Iraq," the UNHCR said in a statement in Jordan, which is being used by UN aid agencies as a foward base to monitor developments in Iraq.

The UNHCR "fears that growing chaos in Iraq's cities and the precarious humanitarian situation could combine to spark the displacement of civilians", the statement said.

It also warned against possible "revenge attacks among certain parts of the Iraqi society" if the security vacuum in Iraq were to continue.

"We urge the occupying forces to take immediate measures to restore and maintain law and order and to ensure that humanitarian assistance flows to those who need it," the statement said.

"War is still ongoing and the euphoria apparent in some cities can be easily replaced by violence. We're very concerned that people may be displaced at this critical stage," the statement added.

Scenes of jubilation mixed with outbreaks of looting erupted across Baghdad Wednesday as US troops advanced through the heart of the Iraqi capital, as President Saddam Hussein's grip on power crumbled.

In Saddam City, Baghdad's teeming Shiite suburb, people were seen breaking into shops and homes to steal furniture, food, electrical equipment and carpets.

In the north of the capital, citizens rampaged through the interior and irrigation ministries, gutting the offices, reporters said, while symbols of Saddam's iron grip on the country took the brunt of people's anger.

There were similar scenes of looting in the southern city of Basra, which is in British hands.

SPACE.WIRE