President Barack Obama, marking the fifth anniversary of Hurricane Katrina in New Orleans Sunday, praised the city's resilience and pledged support for rebuilding "until the job is done."

He acknowledged that the famed jazz city, where at least 1,500 people died in the storm and its aftermath, was still in need of support, but said community efforts had ensured "New Orleans is blossoming once more."

"Together, we are helping to make New Orleans a place that stands for what we can do in America, not just for what we can't do," he said in a speech at the city's Xavier University.

Obama acknowledged that the storm, which brought waves of water that overcame levees carrying homes and residents away, "was a natural disaster, but also a man made catastrophe, a shameful breakdown in government."

But he pledged that the region, struggling with the long-term effects of the tragedy, the economic downturn and, most recently the Gulf of Mexico oil spill, would be able to rely on the administration for support.

"My administration is going to stand with you -- and fight alongside you -- until the job is done," he told a cheering crowd.

Long famed for its rich music scene and its easy-going spirit, New Orleans was plunged into chaos on August 29, 2005 when torrents of water broke through barriers and gushed in.

Although 1.4 million residents and visitors were ordered to evacuate as the monster storm approached, many could not or would not and were left stranded.

A lack of preparation and bungled coordination forced residents to take shelter in attics, and then break through their roofs to escape rising water.

Footage of desperate Americans, waving signs reading "Help Us," horrified people at home and abroad. In the Lower Ninth Ward, the poorest part of the city, built in a basin and 99 percent black, bodies drifted lifelessly with the floodwater.

Many fled to the Superdome, the stadium where 10,000 people displaced by the hurricane had already sought refuge, but it too became cut off by the water.

And rescue services were overrun as the disaster that reached deep into neighboring Mississippi and Alabama unfolded, an entire region deprived of electricity, communications and drinking water.

Finally, the National Guard was deployed, and managed to restore a semblance of order, helping coordinate airlifts and bus evacuations that scattered survivors across the country.

Six days after disaster struck, the Superdome was finally emptied, but it took two months for the floodwaters to subside, and rescuers were still finding bodies more than six months later.

"New Orleans could have remained a symbol of destruction and decay; of a storm that came and the inadequate response that followed," Obama said Sunday.

"But it's a symbol of resilience, of community, of the fundamental responsibility we have for each other."

Ahead of Obama's arrival, the White House touted its commitment to the region, citing efforts to "cut through red tape," and help families still in temporary shelters find more permanent homes.

The administration said it had provided grants to bolster the local justice and health care systems, set up programs to improve handling of emergencies and rebuilt 220 miles (350 kilometers) of levees to pre-Katrina standards.

But many in the city question why the levees are being rebuilt to specifications that failed when Katrina struck.

And five years on, whole neighborhoods in The Big Easy remain abandoned to rot and ruin.

In the lower Ninth Ward, grass and wild plants surround concrete foundation slabs -- stone memorials of the houses that were washed away.

Five years ago, Robert Green was stranded on his roof. He lost his mother and his granddaughter to the floodwaters as the house broke apart underneath his feet.

He now lives in a house built by actor Brad Pitt's Make it Right foundation.

He would like to see the city claim the homes of those who have yet to return, even if that means changing the character of his historic neighborhood.

"The bottom line of it is, we need families, we need young life, young blood," said Green. "We could sit around and wait 20 years for people to come back, or we could realize and say 'So what? I have a Hispanic neighbor, a Vietnamese neighbor,' we've got to open it up."