State, local and federal authorities are grappling with the immense scope of the Hurricane Katrina disaster. The situation is particularly acute in New Orleans, where desperation and anger have contributed to a growing climate of lawlessness.

National Guard troops streamed into New Orleans Thursday as the once-proud city slipped further into chaos in the aftermath of Hurricane Katrina.

Gunfire and looting broke out at points around the city as residents who stayed behind to ride out the storm found themselves in increasingly desperate straits. Acute shortages of such basic commodities as food and drinking water strained people to the breaking point.

Hurricane Katrina cut a deadly path across Louisiana, Mississippi, and Alabama as it came ashore Monday morning. Whole coastal communities were wiped out. The breadth of the destruction has caused some commentators to dub it the "American tsunami" because of its resemblance to the terrible havoc of last year's disaster in Asia.

The situation was underscored at the New Orleans Superdome, the sports complex where some 25,000 people who took refuge from the storm wait in deteriorating conditions to be evacuated to Houston, Texas. Keith Simon of Acadia Ambulance, which is handling medical aspects of the evacuation, told VOA its medical personnel asked to be airlifted out because the mood in the Superdome had turned ugly.

"Our 20 medics, doctors, and nurses, that were at the Superdome felt very uncomfortable about the situation and asked to be removed," he said. "So we moved our people out of the Superdome."

He said they will return when additional National Guard troops arrive and restore order. An additional 10,000 Guardsmen are being deployed to New Orleans and other storm-afflicted areas in addition to the 18,000 already in place.

President Bush expressed sharp anger over the growing lawlessness. In an interview on ABC-TV's Good Morning America, Mr. Bush said there should be what he called "zero tolerance" for looting and price-gouging by people trying to capitalize on others' misfortune. The president plans to visit the hurricane-afflicted areas Friday.

Convoys bearing emergency supplies were moving into New Orleans, a city that is now 80 per cent under water. But the city's remaining residents complained supplies were not reaching them fast enough.

Homeland Secretary Michael Chertoff said Thursday the federal government was working to rescue people stranded in the flooding and provide emergency relief.

"The Department of Homeland Security will continue to work with federal, state, and local partners to support efforts on the ground in Alabama, Louisiana, Mississippi, and Florida," said Michael Chertoff. "We are working tirelessly to make sure that federal resources are being applied where they are needed all across the Gulf [of Mexico]."

The New Orleans flooding occurred when sections of levees holding back the waters that surround the city broke. Hugh Kaufman, a senior policy analyst at the Environmental Protection Agency with long experience in environmental disaster response, says the fetid water presents a major health and enviromental hazard.

"You have a tremendous amount of water that contains sewage, industrial wastewater, hazardous materials, oil, gas, a whole host of hazardous materials that has inundated the whole New Orleans area that has to be dealt with," said Hugh Kaufman.

Officials say they cannot even begin to calculate the human and property damage until the water is removed.