Hundreds of people may have died in Hurricane Katrina's attack on the US Gulf Coast, which sent a wall of water into Mississippi and flooded New Orleans.

US President George W. Bush says the Gulf Coast faces trying times and there's a lot of work to do to recover from the hurricane.

"Right now, our priority is on saving lives and we are still in the midst of search and rescue operations. I urge everyone in the affected areas to continue to follow the instructions of state and local authorities. The federal, state and local governments are working side by side to do all we can to help people get back on their feet." The president spoke at a San Diego naval base as he prepared to cut short his August ranch vacation because of the killer storm.