US President George Bush has admitted there is "frustration" at the speed of the relief effort following Hurricane Katrina's hit on the Gulf Coast.
"I fully understand people wanting things to have happened yesterday. I mean I understand the anxiety of people on the ground... So there is frustration but I want people to know there's a lot of help coming," he said in an interview with ABC television.
He said the operation being mounted was one of the biggest in US history, and inevitably took time to get under way.
"I don't think anybody anticipated the breach of the levees. They did appreciate a serious storm but these levees got breached and as a result much of New Orleans is flooded and now we're having to deal with it and will," he said.
"There's a lot of food on its way, a lot of water on the way and there's a lot of boats and choppers headed that way... it just takes a while to float them."
Mr Bush said there was no figure yet for the number who had died in the hurricane and its aftermath, "but it's obviously going to be a lot".
"We do know that the storm has just blasted the Gulf coast - rural Mississippi and coastal Mississippi - much of it has been obliterated and obviously downtown New Orleans is flooded and so we're trying to get a handle on it. Our first priority of course is the search and rescue," he said.
He condemned the looting reported across New Orleans, saying: "I think there ought to be zero tolerance of people breaking the law during an emergency such as this, whether it be looting, or price gouging at the gasoline pump, or taking advantage of charitable giving, or insurance fraud.
"If people need water and food, we're going to do everything we can to get them water and food.
"But... it's very important for the citizens in all affected areas to take personal responsibility and assume a civic sense of responsibility, so that the situation doesn't get out of hand, so people don't exploit the vulnerable."
The president described his feelings as he flew over the flood scene.
"The devastation that I saw was very emotional, I mean I cannot describe to you what it looks like to see entire neighbourhoods under water or right down the coast in Mississippi to see little communities completely obliterated.
Mr Bush dismissed criticism that he had been slow in responding to the unfolding disaster, and had not yet set foot on the ground.
"I hope people don't play politics during this period of time," he said.
"There'll be ample time for politics. But now's the time to focus attention, our compassion and our resources on helping people who need help".
He said he wanted to go to the scene but did not want to disrupt the emergency operation.
He insisted that New Orleans would be rebuilt in time.
"There's no doubt in my mind as I sit here talking to you that New Orleans is going to rise up again as a great city," he said.