With the evacuation of hurricane affected areas almost complete, the authorities are now turning their attention to the task of finding and identifying the dead.
President Bush remains under pressure for his handling of the crisis, he'll make another trip to the devastated region today.
BBC correspondents report on the latest developments.
Monday Sept 5
Matt Frei, New Orleans 2104GMT
Dawn over New Orleans - or is it Baghdad? - the sky is filled with helicopters.
On the interstate the cavalry has arrived, the 82nd airborne, the heroes of Tikrit now in the French Quarter. There are now 60,000 men under arms in the city and mostly they've been met with bemusement.
It is now virtually deserted but there are one or tow suburbs allowed to return. we meet Mike who is checking his own and his mothers' house. He thinks it will take three or four years for things to return to normal.
President Bush is back in the region, he still hasn't set foot in New Orleans.
In the Hillcrest estate I saw the most encouraging sight of the day, Arthur Smith mowing his lawn, even though all the trees are down.
Jonathan Beale, Washington DC, 1944GMT
A state of emergency now stretches from America's southern states right into the heart of the mid-West - much of the country now affected in the aftermath of Hurricane Katrina.
The White House has now put Florida, West Virginia, Oklahoma, North Carolina, Georgia, Tennessee, Utah, Colorado, Arkansas and Texas in a state of emergency.
All are now eligible for emergency federal funding - from dealing with evacuees from the worst affected states, to protecting public health and safety.
So far, Congress has approved $10.5bn (£5.7bn) worth of emergency aid - a figure that's certain to rise as the clean-up begins.
The states of Louisiana, Mississippi and Alabama, which bore the brunt of the storm, have all been declared major disaster areas.
Daniela Relph, Baton Rouge, 1750GMT
President Bush was accompanied on this visit by T D Jakes, a popular African-American minister and spiritual advisor to the Bush family.
They visited the Bethany World Prayer Centre in Baton Rouge, a Baptist church that is now also a shelter for the displaced.
The president spoke to evacuees and autographed T-shirts for many of the children at the shelter. He also heard from church members who have taken in those who have lost everything into their homes.
Under continuing pressure to explain why the response to this disaster has been so slow and disorganised, the president said there was still a lot of work to be done.
He explained that the priority was still to save lives and what evacuees now needed was food, water, shelter, and love.
Daniela Relph, Baton Rouge, 1610GMT
We've just seen President Bush coming off his plane Air Force One with his wife Laura, do a bit of handshaking on the tarmac and he's now being driven away to a church centre which is now a relief centre to see the work that is being done there.
Although people are relatively glad to be out of New Orleans, to be somewhere safe where they can get clean food and water, many are also complaining about the fact that they've been dehumanised in many ways. They are mostly African- Americans who've been evacuated.
They're arriving here, they're being tagged, they're having a cross put on their hand, they have to go through metal detectors when they arrive, their bags are searched and many say they feel like criminals and not victims at this very vulnerable point in their lives.
So I think there is a little bit of unease in some of these centres and they're also desperate to find a long term solution to their problems - jobs, schools, housing - and there doesn't seem to be any prospect of that at the moment.
Justin Webb, Washington DC, 1545GMT
It hasn't happened yet, but there remains a real possibility that Hurricane Katrina will swamp the Bush administration and leave it wrecked beyond repair.
On the face of it, the inquiries, which will start this week on Capitol Hill, would appear to be a big threat to the president. But, it may well be that other targets loom larger once the searching questions begin - targets which will include America's entire system of government, which has proved itself to be incapable of coping with a big disaster on its doorstep.
The nation is proud of its local democracy and local power, but a bewildering array of competing fiefdoms hampered the management of this crisis and may well need to be swept away - a change requiring a fundamental cultural shift in how the United States is governed.
Jon Sopel, New Orleans, 1510GMT
Hundreds of thousands have been evacuated from the city and other areas along the Gulf coast.
Nothing quite prepares you, driving into New Orleans and seeing road after road where nobody moves, nothing is moving and not a car on the street. It really is a very eerie scene indeed.
Now they are talking about sending people where there are plenty of hotel rooms. They are talking about Miami, they are even talking about sending some of the people who have been evacuated to Las Vegas because they would be able to cope with the influx of people.
Jeremy Cooke, New Orleans, 1220GMT
There is a huge military presence here. It feels, smells and looks like a war zone.
The military are here in huge numbers. Their task is to restore law and order, recover bodies and generally to bring this situation under control.
They are well-armed and patrolling in a way that has made people feel they are preparing for a conflict rather than to help. It's an issue that local people are starting to talk about. There is a lot of discomfort, a lot of distress about what they consider an inappropriate response to this disaster.
Matthew Davis, New Orleans, 1210GMT
The security situation appears to be improving. There are more people on the streets this morning. Although many have been airlifted and bussed out of the city, many are staying put, surviving on very little.
Jeremy Cooke, New Orleans, 1205GMT
Some people from the more outlying areas of New Orleans are now being allowed back into their homes to assess the damage. Just one member of each household, but it is a small step forward.
But we're under no illusions. This is a city still in the grips of a major crisis.
Jamie Coomarasamy, New Orleans, 1136GMT
Even in a city packed with armed police and soldiers, there is still the potential for disorder. Four men were killed in New Orleans yesterday after a shoot-out with police officers near a bridge.
The victims had allegedly been firing on state employees involved in the reconstruction effort. Yet, despite the tension there are people returning here, if only briefly. In Jefferson parish, long queues began forming in the early hours of the morning for the chance to see the damage done to their homes.
The authorities here are allowing people to salvage their possessions, but asking them to leave again. Also returning to the region for the second time in three days is President Bush. He will be taking stock of the relief effort in Mississippi and Louisiana.
Bill Turnbull, New Orleans, 0835GMT
The city is virtually empty, only a few stragglers remain, but New Orleans is still in the grip of an emergency.
In the past 24 hours alone we've seen a helicopter crash and what appears to have been a gun battle with deadly consequences.
Not only is there is a very heavy police and military presence here, we've also seen pickup trucks full of ordinary citizens brandishing shotguns, being paid by the authorities to keep law and order.
Graham Satchell, Houston, 0800GMT
Latest estimates suggest there are now 250,000 people here in Houston from Louisiana.
The authorities are struggling to cope with such an influx but local people and churches have been doing what they can, providing food and clothing, and taking survivors into their homes.
Bill Turnbull, New Orleans, 0715GMT
The authorities are now focusing on finding and identifying the dead.
It's ghastly when you think about it because the water is still here, so they will have to wade house to house to check every building, every floor, every room, to see if there are dead people inside.
If there are, those bodies will have been in there in high humidity and 90 degree heat for several days. It is a deeply unpleasant task but it has to be done.
Michael Buchanan, Houston, Texas, 0519GMT
The former American presidents Bill Clinton and George Bush Senior, will visit Houston to launch a fund-raising drive to help victims of Hurricane Katrina today.
This will be the second time that Bill Clinton and George H W Bush have crossed America's political divide to raise money for disaster victims.
Following last year's tsunami in Asia, the two former presidents spearheaded a global fund-raising effort that raised more than a billion dollars. As then, the two men have been brought together by President Bush, who wants to bring some focus to the multiple efforts currently under way by scores of charities.
Americans have already dug deeper and faster into their pockets for the victims of Hurricane Katrina than ever before. Less than a week since the storm struck, more than four-hundred-million dollars has been pledged, mostly through the Red Cross.
Jamie Coomarasamy, New Orleans, Louisiana, 0314GMT
Exactly a week after Hurricane Katrina struck, the first of the evacuees from New Orleans are returning, if only for a while.
In Jefferson parish, to the west of the city, residents are being allowed past checkpoints to view and clear their homes but they have to leave again by Thursday.
Elsewhere in the city, the search for survivors -- and increasingly for bodies, continues in conditions that remain tense.
On Sunday New Orleans police shot and killed four men who were said to have been looting, while a civilian helicopter involved in the rescue efforts crashed, although no casualties were reported.
President Bush arrives in the area for his second visit in just three days as his government struggles to undo the political damage caused by its initial response to the disaster.
Justin Webb, Washington DC, 0256GMT
President Bush is to visit the devastated Gulf coast of the United States again today, Monday, as his administration continues its efforts to convince Americans that it can cope with the aftermath of the hurricane.
For the White House nothing else matters now. The President's schedule for the entire month of September has been torn up.
A visit by the Chinese president due this week has been cancelled. Much of the administration's second-term agenda has been set aside for the time being.
Instead the administration is engaged in two struggles, the first to improve its performance on the ground in the hurricane-hit regions, and the second, to convince America that the White House is not to blame for what went wrong.
President Bush will tour the area again today but his suggestion over the weekend that local officials had failed to cope has raised hackles in the south.
A Louisiana Senator, Mary Landrieu, has threatened to punch Mr Bush if he says it again. An opinion poll in the Washington Post suggests that, as ever, the nation is evenly divided on the Bush performance. Half think he's doing a good job, half do not.