US President George W. Bush, facing scathing criticism of the government response to Hurricane Katrina, has conceded the relief effort was unacceptable as he visited the ravaged Gulf Coast this afternoon.
"Where it's not working right, we're going to make it right," Bush said. "We are going to restore order in the city of New Orleans."
The US president said the destruction looked "as if the entire Gulf Coast were obliterated by the worst kind of weapon you can imagine."
Mr Bush was speaking in Mobile, Alabama, where he was briefed by emergency officials. The president is expected to go on to visit Mississippi and Louisiana - but not New Orleans itself.
He spoke as criticism mounted of his administration's response to likely the nation's worst natural disaster, including the adequacy of its funding for New Orleans' levees and its readiness for the disaster. Concerns were also growing over the US economy as gasoline prices surge above $3 a gallon.
Anarchy and looting have broken out in flooded New Orleans, tens of thousands across the area remain stranded and without adequate food and water, and local officials are warning of a death toll that could number in the thousands. Only half of the 30,000 National Guard and military troops so far dispatched are in place.
The first emergency military convoy of aid supplies arrived in New Orleans this evening to help in the relief of tens of thousands of refugees made desperate in the aftermath of Katrina.
In Washington, congressional black leaders said the black and poor population of New Orleans was suffering disproportionately.
"In the last 140 or so hours we have witnessed something shockingly awful, and that is the lack of response, a quick response, from our government to those Americans who are suffering or dying," said Illinois Rep. Jesse Jackson Jr., son of the civil rights leader.
Katrina's aftermath presents Bush with his greatest emergency since the Sept. 11, 2001, attacks. He has already been struggling with the lowest approval ratings of his presidency amid rising discontent with the Iraq war.
Before leaving the White House for Louisiana, Mississippi and Alabama to view damage, Bush was blunt in his appraisal of what had been done in the four full days since the deadly storm struck on Monday morning.
"The results are not acceptable," Bush said.
Bush cut his holidays short by two days to return to Washington on Wednesday to oversee the recovery. His request of a quick $10.5 billion in aid was approved by the US Senate and was set for swift passage by the House of Representatives.
Bush insisted, "We'll get on top of this situation and we're going to help people who need help."
"The federal government's job is big and its massive and we're going to do it," he said at his first stop in Mobile.
McClellan said Bush was aware of the angry criticism of the relief effort from New Orleans Mayor Ray Nagin. He defended the federal government's response, saying the disaster was of an unprecedented scale.
Bush was to later tour the Alabama-Mississippi coast by helicopter then take a walk through damaged areas in Biloxi, Mississippi.