While seemingly reluctant to accept foreign offers for help, saying that the US could “take care of it”, US President George W Bush readily called on his father, George Bush Snr, and former president Bill Clinton to drive private fundraising initiatives.
From longstanding allies such as Australia, Britain and Canada, to tempestuous Venezuela and impoverished Honduras, the offers have been flooding in.
Australian Prime Minister John Howard said he had contacted US officials with an offer of 20 emergency experts a day after he also had two specialist emergency managers placed on standby to head over.
“There should not be an assumption that because America is the wealthiest and most powerful country in the world this isn’t a major challenge and a major crisis,” Mr Howard said.
Assistance from other countries ranged from offers of medical teams, boats, aircraft, tents, blankets, generators and cash donations.
Venezuelan President Hugo Chavez set aside his usual anti-American animosity to make available humanitarian aid, relief workers and cheap fuel.
The very real problem of the United States’ diminished oil supply is expected to draw a request from the Bush administration for cheap oil supplies from oil-rich Arab nations and other producers in the coming days.
“Americans should be prudent in their use of energy during the course of the next few weeks. Don’t buy gas (petrol) if you don’t need it,” Mr Bush warned.
Nine refineries in the Gulf of Mexico are closed, affecting about 10 percent of total US output, and 487 platforms and rigs in the region remain evacuated.
A massive swathe of destruction litters the Gulf coastline and at least 126 people are reported to have been killed in the state of Mississippi, but it is believed the death toll is in the thousands.
Seven people were killed in Florida on August 25 when Katrina first surged across the Caribbean.
The states of Louisiana and Alabama have also experienced severe losses.
Tens of thousands of homes and businesses have been destroyed and more than 78,000 people left homeless.
Among the thousands of people unaccounted for is New Orleans’ legendary boogie-woogie piano man, Fats Domino.
The 76-year-old’s manager Al Embry said he had been in telephone contact with the musician before Hurricane Katrina hit and tried to persuade him and his wife Rosemary to leave the city.
Mr Embry said Mr Domino’s home is in New Orleans’ 9th Ward, an area now believed to be under water.
US Homeland Security Secretary Michael Chertoff is coordinating the relief effort which is concentrated most heavily on the city of New Orleans.
Fifty disaster medical teams have been dispatched to the flooded Louisiana port, and a further 28 urban search and rescuers.
Thousands of generators, blankets, cots and more than 13 million litres of drinking water have been sent in and a network of 40 medical centres with 10,000 beds and 4,000 staff has been set up.
Meanwhile, meteorologists are keeping an eye on further storm activity off the US, with Tropical Storm Lee forming in the Caribbean.
America’s Gulf coast is in no shape to handle more wild weather.
Monitoring from the US Geological Survey has shown that much of the shoreline from Florida to Louisiana has suffered damage to its natural defences against storm surges, including sand dunes and marshes.