US Coast Guard Vice Admiral Thad Allen, the man in charge of the federal relief and rescue effort, has made it clear he would try to persuade Mayor Ray Nagin not to rush his plan to repopulate New Orleans three weeks after Hurricane Katrina flooded most of the southern city.

Allen said Sunday districts still lacked potable water and reliable power and there were high levels of the diarrhea bacteria E. coli in the environment.

"Our collective counsel is for him to slow down and take this at a more moderate pace," he said on Fox television. He added that he would give a "frank, unvarnished assessment" to the mayor.

Hundreds of people died in floods after the hurricane hit the low-lying city and breached protective dams, or levees, around it.

Allen said, "Everybody supports the mayor in wanting to get New Orleans started again. In the view of the federal community, which I represent down here, it's more of a matter when you are ready to go in."

"There is no potable water.

"The standing water has high concentrations of E. coli and the levees have been weakened to the point where if you bring a significant amount of people into New Orleans you need to have an evacuation plan and how are you going to do that?"

In a reminder that the situation in the region remains tense, a Biloxi, Mississippi, man frustrated with the recovery effort was arrested Sunday on charges of threatening to bomb disaster relief agencies.

Billy Wayne Livingston, 39, is accused of making telephone threats to representatives of the American Red Cross, the Federal Emergency Management Agency and Keesler Air Force Base.

Livingston, whose home was destroyed by the hurricane, made he was dissatisfied with the assistance he has received since the storm.

Meanwhile, business people were allowed back to the city's French Quarter and other central districts this weekend.

But only a tiny trickle of entrepreneurs showed up.

Jewelry and antique shops, restaurants and souvenir stores remained boarded up while garbage crews picked up rubbish, trees, food and other debris.

Nancy Easterling lost her home to a layer of black-and-brown sludge. "Everything is destroyed," she said.

Although her business downtown escaped flooding, looters stole her catering van. She knows because she actually saw it on CNN -- careering down the chaotic streets of New Orleans after the storm.

She inspected her business, Food Art, for the first time Sunday. She plans to reopen, although half her events were at the convention center, which is closed.

"We'll be ready to get up and running in no time," said Easterling, because emergency workers and journalists get hungry, too.

"I think that there will be a lot of people in need of food."

Nagin's plan -- unveiled last Thursday in full media glare -- is to breathe life back into a city that was turned into a ghost town by Katrina.

People would return by districts to the least-hit areas, so that 180,000 people, of a pre-storm population of half a million, would return by October.

Those returning will receive a two-page information package at checkpoints.

Residents were advised to bring in all their food and water, the local newspaper, the Times-Picayune said.

Katrina slammed into the Gulf of Mexico coastline of Louisiana, Mississippi and Alabama on August 29, killing 880 according to the latest toll Sunday.

Around one million people left their homes and around 100,000 are still living in shelters. Tens of thousands of others are staying with relatives or in temporary accommodations.

As for the economic cost, estimates of the final tab remain speculative, with some figures in the region of 200 billion dollars.

Katrina also plunged President George W. Bush into one of the worst crises of his presidency.

His opinion-poll standing sank to new lows as voters widely faulted him for failing to help tens of thousands of people trapped in New Orleans as floodwaters rose, food and water ran out and looters took over the streets.

Bush will visit the Gulf disaster zone again on Tuesday, his fourth visit to the region, the White House said.

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