President George W Bush has defended the government's response to Hurricane Katrina and pledged more help on a trip marking the storm's first anniversary.
Mr Bush acknowledged ongoing concerns in the storm-hit region
"This is my 11th visit since the storm hit. You see progress," he said in Biloxi, Mississippi, his first stop.
He is due to spend Tuesday - a national day of remembrance - in New Orleans, the city hardest hit by Katrina.
About 1,500 people died when the storm struck Mississippi and Louisiana on 29 August, and thousands became homeless.
The White House was harshly criticised for what was seen as a slow response to the country's worst natural disaster.
Mr Bush acknowledged the ongoing frustration of the people of the region in his speech in Biloxi.
"A year ago, I committed our federal government to help you," he said.
"I meant what I said. We have appropriated $110bn to help rebuild this area," he said, sunburned and sweating in the heat during his outdoor speech.
"We understand people are still anxious to get into their homes. People hear about help and wonder where it is. We know that."
He also praised the contribution of local business leaders, educators and clergy in responding to the disaster and helping with reconstruction.
"We can work together and will, but when disaster strikes, the first people that you rely upon are your friends.
"It was the bravery of the local citizens that made the difference between life and death" when the hurricane hit, he said.
New storm coming
The president's visit to the affected region comes amid warnings that Tropical Storm Ernesto - currently pounding the Caribbean - could hit Florida with increased force this week.
Aides said that, over the weekend, Mr Bush had been kept informed about the storm - which grew into a hurricane on Sunday before weakening.
Mayor Nagin has pledged to save historically black areas
Mr Bush met community leaders in Biloxi and walked through a damaged neighbourhood.
He will also visit the town of Gulfport, before heading off to New Orleans in neighbouring Louisiana, where he will have dinner with state and local officials.
On Tuesday, Mr Bush is scheduled to have breakfast with Mayor Ray Nagin, who has been very critical of both the federal and the state reaction to the hurricane.
Much of New Orleans was left under water after the city's flood defences were overwhelmed.
Those who had no means to escape before the storm struck - mainly the poor and elderly - were left behind. The scenes of misery and desperation that followed shocked the world.
One year on, many of the areas devastated by the floods have yet to be rebuilt and re-populated.
Fewer than 200,000 of the original half-million inhabitants have returned.
Mr Nagin has said he believes it will take about five years for population levels to recover.
He has also pledged to defend historically black neighbourhoods from destruction - even though some have argued that that may be economically and environmentally unwise.