President George W Bush has arrived in New Orleans to mark the first anniversary of Hurricane Katrina, the storm that wiped out much of the city.
George Bush toured Biloxi's rebuilding projects
He will attend a church service and meet local people on what has been declared a national day of remembrance.
The anniversary has revived criticism of the government's slow response to the crisis.
On Monday Mr Bush defended the response, said New Orleans was recovering, and pledged more help.
"This is my 11th visit since the storm hit. You see progress," he said in Biloxi, Mississippi, his first stop on a tour of the devastated Gulf Coast.
Nearly 1,700 people died when the storm struck Mississippi and Louisiana on 29 August, and thousands became homeless.
1,695 people killed and 153 still missing
78,000 homes in New Orleans destroyed
Population has fallen from 455,000 before Katrina to about 200,000
Suicide rates have trebled
Mr Bush acknowledged the ongoing frustration of the people of the region.
"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."
Mr Bush is scheduled to have breakfast on Tuesday with New Orleans Mayor Ray Nagin, who has been very critical of both the federal and the state reaction to the hurricane.
Later in the day wreaths will be laid in the still-devastated neighbourhoods and at the site of each of the levees that succumbed to the mass of water dumped on the city by the storm.
Many houses in New Orleans are still choked with mud and debris
A jazz funeral procession will take to the streets, paying respects to those who died.
One year on, many of the areas devastated by the floods have yet to be rebuilt and re-populated.
Only about 200,000 of the original near-half-million inhabitants have returned.
The White House says the president is behind the rebirth of the entire region - but in New Orleans that rebirth appears painfully slow, says the BBC's Andy Gallacher.
Surveying the devastation that remains, our correspondent said it was hard to believe anyone ever lived in the crumbled, mud-choked buildings.
He described the disgusting smell in a house where the skeleton of a dead dog lay near a child's doll and scattered personal documents.
Critics say many of those promised federal and state assistance to rebuild their homes are still waiting to receive it.
And with many of the city's former residents now dispersed across the rest of the US, there are fears that New Orleans will never regain its former character.
Mr Nagin hopes population levels will recover, even if it takes five years.
He has also pledged to defend historically black neighbourhoods - some of those worst-hit - from destruction.
More than half of the city's pre-Katrina residents were African-Americans, and surveys show many believe it is extremely important that the city retains its previous racial balance.
But some worry that only those in wealthy neighbourhoods will remain and the reconstruction of the city will be planned without those who previously made up the majority of its population, our correspondent says.