The wild chaos has pushed the hurricane-hit city New Orleans into a state of anarchy on Thursday, as bodys lay forsaken, fights and fires can be seen everywhere and looters run wild in the street.

Frustration, fear and anger mounted four days after Hurricane Katrina's devastating blow inflicted potentially thousands of deaths, despite the promise of 1,400 National Guardsmen a day to stop the looting, plans for a $10 billion recovery bill in Congress and a government relief effort President Bush called the biggest in US history.

New Orleans' top emergency management official called chaos a "national disgrace" and questioned when reinforcements would actually reach the increasingly lawless city.

About 15,000 to 20,000 people who had taken shelter at New Orleans convention center grew increasingly hostile after waiting for buses for days amid the filth and the dead.

Police Chief Eddie Compass said there was such a crush around a squad of 88 officers that they retreated when they went in to check out reports of assaults.

"We have individuals who are getting raped, we have individuals who are getting beaten," Compass said. "Tourists are walking in that direction and they are getting preyed upon."

Amid scenes of utter chaos, a military helicopter came under fire as it tried to lift refugees from New Orleans' Superdome sports stadium, while a hospital was abandoned after an armed gang held up a supply lorry bringing in food, water and medical supplies.

"The truth is, a terrible tragedy like this brings out the best in most people, and brings out the worst in some people," said Haley Barbour, the governor of neighbouring Mississippi, vowing to deal with looters in his state as "ruthlessly as we can get our hands on them".

The US president, George W. Bush, who is due to visit the area today, warned there should be "zero tolerance" for those breaking the law during an emergency situation.

As many as 30,000 National Guard troops are expected to be mobilised soon, and the US Navy is sending the aircraft carrier Harry S Truman to help with rescue efforts.