A day-by-day look at how the crisis has unfolded in New Orleans, after the city was battered by Hurricane Katrina.
FRIDAY 9 SEPTEMBER
The US government announces the removal of Federal Emergency Management Agency (Fema) director, Michael Brown, from his role of managing the Hurricane Katrina relief effort on the ground.
He is replaced by Coast Guard Vice-Admiral Thad W Allen, but will remain at the helm of Fema, Homeland Security Chief Michael Chertoff says.
The man in charge of the relief operation has been replaced
Meanwhile, the US public pledges around $587m (£319) in aid - more than initial donations for 9/11 and the Asian tsunami.
Former US Secretary of State Colin Powell says "not enough was done" to prevent this tragedy, despite plenty of warning over time about the dangers to New Orleans.
A poll finds that two-thirds of Americans think President George W Bush could have done more to tackle the floods and damage in the south.
THURSDAY 8 SEPTEMBER
US President George W Bush declares Friday 16 September a national day of remembrance for those who lost their lives in the aftermath of Hurricane Katrina.
With the official death toll for New Orleans still at 83, 25,000 body bags are sent to the city where thousands of people are feared to have died.
Vice-President Dick Cheney tours the flood-stricken area
Meanwhile, the Federal Emergency Management Agency starts handing out debit cards worth up to $2,000 (£1,090) per household to registered evacuees as an initial financial aid pledged by President George W Bush.
Vice-President Dick Cheney visits affected areas to inspect damage and overview the relief effort.
WEDNESDAY 7 SEPTEMBER
The White House says it is seeking an additional $51.8bn (£28bn) to fund relief efforts in the southern US, following a $10.5bn (£5.7bn) approved by Congress last week.
The authorities in New Orleans confirm that five people have died after contact with flood waters, containing unsafe levels of E. coli and other bacteria as well as high levels of lead.
As the flood waters in the city slowly begin to recede, emergency crews face a grim task of recovering bloated bodies amid fears that thousands may have died.
US politicians join calls from the public and the media for senior government officials to admit they were slow to respond to Katrina.
The hurricane may knock as much as 0.5% off the US' annual gross domestic product (GDP), US Treasury Secretary John Snow forecasts.
Meanwhile, the Congressional Budget Office says 400,000 people may have lost their jobs as a result of Katrina.
TUESDAY 6 SEPTEMBER
Engineers begin pumping water from New Orleans after repairing a key breach in the city's floodwalls, eight days after Katrina struck.
Mayor Ray Nagin orders the forced evacuation of anyone still in the city, amid serious health fears.
Amid mounting criticism of the federal emergencies agency, US President George W Bush says he will lead an investigation into how the disaster was handled.
MONDAY 5 SEPTEMBER
Residents who fled Hurricane Katrina are allowed to return briefly to inspect their homes in New Orleans and collect personal items. An 1800 curfew is set.
Rescuers still scour streets and homes to find survivors - it is estimated that 10,000 people remain in the flooded city.
President Bush makes his second trip in three days to the area.
Two of his predecessors - George Bush Sr and Bill Clinton - join forces to launch a national appeal.
SUNDAY 4 SEPTEMBER
New Orleans is left almost deserted after thousands of survivors are flown out to neighbouring states.
The administration says security has been restored in the city and full federal help is in place.
For the first time since the hurricane struck, the US appeals for international aid, requesting blankets, first aid kits, water trucks and food.
Visiting New Orleans, Defence Secretary Donald Rumsfeld says it could take years for the city to recover.
Meanwhile US Secretary of State Condoleezza Rice rebuffs criticism that the government was slow to respond to the emergency, saying "Nobody, especially the president, would have left people unattended on the basis of race."
US Health and Human Services Secretary Michael Leavitt says the death toll from Katrina will be in its thousands - the first such acknowledgement by a federal official.
He says recovery workers will have to go from house to house and warns of grim days ahead.
SATURDAY 3 SEPTEMBER
What is described as the largest airlift operation in US history gets under way.
More than 10,000 people are removed from New Orleans - the Superdome stadium and the city's convention centre are cleared. Evacuees recount scenes of violence, including rapes and murders at the shelters.
Relief workers open a mortuary and begin collecting corpses, many of which have been floating in the flooded streets of New Orleans for days.
Meanwhile, amid mounting political pressure, President George Bush announces the deployment of thousands more front-line troops into the areas devastated by Hurricane Katrina.
In a national televised address, he acknowledges that many "citizens simply are not getting the help they need, especially in New Orleans".
FRIDAY 2 SEPTEMBER
The relief effort in New Orleans is stepped up. Evacuations continue as military convoys arrive with supplies of food, medicine and water.
Extra National Guard units are brought into New Orleans to tackle the looting and general lawlessness which has spread across the city.
It is still not known how many people have died as a consequence of Katrina, but a Republican Senator in Louisiana, David Vitter, says the number could reach 10,000.
Tens of thousands of people are still stranded - some of them are still waiting to be rescued from rooftops of houses surrounded by water.
Meanwhile, President Bush promises long-term help for reconstruction during a visit to affected areas, having acknowledged that the initial response had not been acceptable. Congress approves a $10.5bn emergency spending package.
THURSDAY 1 SEPTEMBER
New Orleans descends into anarchy, with reports of looting, shootings, carjackings and rapes. The local police force is ordered to focus its efforts on tackling lawlessness.
Buses and helicopters begin to take the most vulnerable out of the Superdome stadium - some will go to the Louisiana state capital, Baton Rouge, others to the Astrodome stadium in Houston, Texas.
Shots reportedly fired at a helicopter airlifting people from the stadium slow down the evacuation process.
Anger mounts over the delay in getting aid to people in New Orleans and what is seen as an inadequate response from the federal government.
WEDNESDAY 31 AUGUST
Mayor Ray Nagin says the hurricane has killed hundreds, possibly thousands. He orders the full evacuation of the city - up to 100,000 residents are still said to be there.
Many try to battle their way through the water to the city's Superdome stadium in search of refuge. Tens of thousands of people end up there, but conditions inside the stadium are deteriorating fast.
Armed police try to impose a form of martial law to stem looting - while some looters are stealing non-essential goods, others are simply trying to find food and water.
Cutting short a holiday in Texas to take charge of the federal recovery effort, President Bush says the government is dealing with one of the worst natural disasters in US history.
The government declares a public health emergency along the whole of the Gulf coast, to speed up the delivery of food, water and fuel to the region. It is announced that extra troops are also being sent.
TUESDAY 30 AUGUST
The scale of the devastation caused by Hurricane Katrina and the subsequent flooding becomes clearer.
About 80% of the low-lying city is under water. Helicopters and boats are picking up survivors stranded on rooftops across the area - many are to spend several more days there.
Rescuers are said to be pushing aside the dead bodies floating in the water, as they try to reach survivors.
With some of the city's flood defences breached, the situation is getting more desperate as waters continue to rise.
Hundreds of people are feared dead along the Mississippi coast.
MONDAY 29 AUGUST
Hurricane Katrina hits the Gulf coast, wreaking havoc in the states of Louisiana, Mississippi and Alabama.
Many areas of New Orleans are flooded and winds of more than 100mph (160km/h) tear off part of the roof of the Superdome stadium where some 9,000 people are taking refuge.
Power lines are cut, trees felled, shops wrecked and cars hurled across streets strewn with shattered glass.
There are reports that some of the city's flood defences have been breached.
SUNDAY 28 AUGUST
Hurricane Katrina gains strength over the Gulf of Mexico - having already battered the state of Florida. Fears grow for New Orleans, which sits some 6ft (2m) below sea level.
Mayor Ray Nagin orders the mandatory evacuation of the city after the storm becomes a maximum-strength Category Five hurricane.
Motorways are jammed as people obey the order to leave.
Some of those unable or unwilling to leave spend the night in shelters - including the Superdome stadium.