NEW ORLEANS (AP) – Storm victims were raped and beaten, fights and fires broke out, corpses lay out in the open, and rescue helicopters and law enforcement officers were shot at as hurricane-flooded New Orleans descended into anarchy yesterday.

“This is a desperate SOS,” the mayor said.

Anger mounted across the ruined city, with thousands of Hurricane Katrina victims increasingly hungry, desperate and tired of waiting for buses to take them out.

“We are out here like pure animals. We don’t have help,” the Rev Issac Clark, 68, said outside the New Orleans Convention Centre, where corpses lay in the open and evacuees complained that they were dropped off and given nothing – no food, no water, no medicine.

About 15,000 to 20,000 people who had taken shelter at the convention centre to await buses grew increasingly hostile. Police Chief Eddie Compass said he sent in 88 officers to quell the situation at the building, but they were quickly beaten back by an angry mob.

“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.”

In hopes of defusing the unrest at the convention centre, Mayor Ray Nagin gave the hurricane victims permission to march across a bridge to the city’s unflooded west bank for whatever relief they can find. But the bedlam at the convention centre appeared to make leaving difficult.

A military helicopter tried to land at the convention centre several times to drop off food and water. But the rushing crowd forced the choppers to back off. Troopers then tossed the supplies to the crowd from 10 feet (3 metres) off the ground and flew away.

National Guardsmen poured in to help restore order and put a stop to the looting, carjackings and gunfire that have gripped New Orleans in the days since Hurricane Katrina plunged much of the city under water.

In a statement to CNN, Nagin said: “This is a desperate SOS. Right now we are out of resources at the convention centre and don’t anticipate enough buses. We need buses.

Currently the convention centre is unsanitary and unsafe and we’re running out of supplies.”

In Washington, Homeland Security Secretary Michael Chertoff said the government was sending in 1,400 National Guardsmen a day to help stop looting and other lawlessness in New Orleans. Already, 2,800 National Guardsmen are in the city, he said.

But across the flooded-out city, the rescuers themselves came under attack from storm victims.

“Hospitals are trying to evacuate,” said Coast Guard Lt Cmdr Cheri Ben-Iesan, spokesman at the city emergency operations centre. “At every one of them, there are reports that as the helicopters come in people are shooting at them.

There are people just taking potshots at police and at helicopters, telling them, ‘You better come get my family’.”

Some Federal Emergency Management rescue operations were suspended in areas where gunfire has broken out, Homeland Security spokesman Russ Knocke said in Washington. “In areas where our employees have been determined to potentially be in danger, we have pulled back,” he said.

A National Guard military policeman was shot in the leg as he and a man scuffled for the MP’s rifle, police Capt Ernie Demmo said. The man was arrested.

Outside the Convention Centre, the sidewalks were packed with people without food, water or medical care, and with no sign of law enforcement. Thousands of storm refugees had been assembling outside for days, waiting for buses that did not come.

At least seven bodies were scattered outside, and hungry people broke through the steel doors to a food service entrance and began pushing out pallets of water and juice and whatever else they could find.

An old man in a chaise lounge lay dead in a grassy median as hungry babies wailed around him. Around the corner, an elderly woman lay dead in her wheelchair, covered with a blanket, and another body lay beside her wrapped in a sheet.

“I don’t treat my dog like that,” 47-year-old Daniel Edwards said as he pointed at the woman in the wheelchair. “I buried my dog.” He added: “You can do everything for other countries but you can’t do nothing for your own people. You can go overseas with the military but you can’t get them down here.”

The street outside the centre, above the floodwaters, smelled of urine and faeces, and was choked with dirty diapers, old bottles and garbage.