A full week after Katrina crashed into the US Gulf coast and destroyed one of America's most popular cities, the home of jazz and Mardi Gras, no one knows how many people perished.

New Orleans Mayor Ray Nagin said "it wouldn't be unreasonable" for the death toll to rise to 10,000, although he admitted he had no idea of the exact number.

As the government tried to regain control, police pleaded with New Orleans' remaining survivors to abandon the city.

"There are no jobs. There are no homes to go to, no hotels to go to, there is absolutely nothing here," Deputy Police Chief Warren Riley said. "We advise people that this city has been destroyed, it has completely been destroyed."

Forensic experts prepared a warehouse for the grim task of identifying victims when they are finally recovered.

Some are not hard to find as swollen bodies float in the streets but officials fear thousands more are hidden in homes across New Orleans, the home of jazz and Mardi Gras and one of America's most popular cities before Katrina tore it apart,

In suburban Jefferson Parish, stunned residents got a first look at Katrina's damage to their homes when it struck with 140 mph (225 kmh) winds and a massive storm surge.

They were greeted by a panorama of toppled trees and street signs, and spacious middle-class homes that had been flooded with several feet of water.

"I try to be upbeat but it's devastating. I may lose my house because I may not be able to make my payments, and I don't know when I'm going to work again," said Mark Becker, 48, at his Metairie home.

Storm winds had ripped two holes in his roof and caused the ceiling to collapse in a bedroom and kitchen.

Others said the damage could have been worse. They said their homes were mostly intact and salvageable.

Many of those going back brought guns or friends or both for protection in case they encountered looters.

The Jefferson Parish government told its residents not to stay in their homes, but to gather items they needed and leave again by nightfall because there was no power or clean water.

BUSH UNDER FIRE

Bush, who has faced fierce criticism for the slow relief response, visited dozens of Katrina victims being cared for at a prayer center in Baton Rouge and promised the country would "do what it takes" to help people get back on their feet.

It was the second trip to the ravaged region in less than a week for Bush, already suffering from the lowest approval ratings of his presidency, largely because of the Iraq war.

He has admitted the early relief effort was "unacceptable" and promised on Monday to make changes as needed.

"If it's not right, we're going to fix it, and if it is right, we're going to keep doing it. And this is just the beginning of a huge effort," Bush said.

Former President Bill Clinton joined the growing criticism of the government response. "Our government failed those people in the beginning. There is no dispute about it," he told CNN.

The New Orleans Times-Picayune called on Bush to fire every official at the Federal Emergency Management Agency. "We're angry, Mr. President," the newspaper said in an open letter.

Former President George H.W. Bush, said he didn't like to see his son under fire but that it was part of the job.

"The president can take it," he said. "It goes with the territory."

The official death toll in Louisiana stood at 59 but officials said it would climb dramatically in coming days.

A warehouse in a Louisiana town is being set up to handle thousands of corpses. Rows of stainless steel gurneys await the first bodies and the concrete floors are covered with plastic sheets to contain fluids that could pose a biohazard threat.

Temporary morgues were being set up around the region.

More than 100 deaths are confirmed in Mississippi and many more are feared buried under piles of rubble or hidden in attics where they took refuge from rising waters.

REGAINING CONTROL

Police and troops were regaining control of the city after days of murder, rape and looting that horrified America and the world.

Lights were going on in some neighborhoods of the stricken city as the local power company began restoring electricity.

The US Army Corps of Engineers said it had made progress in repairing levees and began pumping water out of a flooded district on Monday. Still, draining the entire city could take 80 days or more.

Two cruise ships based in Galveston, Texas, were expected to start boarding evacuees later on Monday. They both have a capacity for 2,600 people.

At least 240,000 evacuees had flooded into neighboring Texas, where Gov. Rick Perry said the state could handle no more and asked that any more be airlifted to other states.

Not all New Orleans residents wanted out. "They'll have to drag me out by my feet," said Mike Reed, 49, as he swept debris from the streets of the city's historic French Quarter, which experienced light flooding compared with other neighborhoods.