"Better days are ahead," Mr. Bush said as he sought to assure residents that his administration had not forgotten the region and would make good on the promises of aid.
"We're still paying attention. We understand," the president said at a recovering school in the Lower Ninth Ward, a predominantly black, low-income area that was all but obliterated by the storm.
Wreaths were laid, prayers were said, and bells were rung across New Orleans to commemorate this day two years ago when Katrina went from being a name to a nightmare, reports CBS Evening News anchor Katie Couric.
Katrina was a Category 3 hurricane when it hit the Gulf Coast, broke through levees in New Orleans and flooded 80 percent of the city.
The storm ravaged the city, and despite many promises to rebuild, much of New Orleans remains in ruins, adds Couric.
"We fully understand New Orleans can't be rebuilt until there is confidence in the levees," President Bush said Wednesday.
By the time the last of the water dried up weeks later, more than 1,600 people across Louisiana and Mississippi were dead, and a shocked nation was looking at miles of wrecked homes, mud and debris from the worst natural disaster in its history.
"We ring the bells for a city that is in recovery, that is struggling, that is performing miracles on a daily basis," Nagin said at a groundbreaking ceremony for a memorial that will be the final resting place for more than two dozen still-unidentified victims.
After he spoke, a large bell tolled a dozen times and a crowd rang hand-held bells for more than a minute to remember the victims.
"The saddest thing I've seen here is that there are 30 human beings who will be buried here one day that nobody ever called about," said David Kopra, a volunteer from Olympia, Wash., holding back tears. "It says something to my heart. This city needs so much care."
The front page of The Times-Picayune advertised a scathing editorial above the masthead: "Treat us fairly, Mr. President." It chided the Bush administration for giving Republican-dominated Mississippi a share of federal money that it said was disproportionate to the lesser impact the storm had there than in largely Democratic Louisiana. "We ought to get no less help from our government than any other victims of this disaster," it said.
Protesters, remembering the government's slow response in the storm's immediate aftermath, planned to march from the Lower 9th Ward to Congo Square to spread their message that the government has also failed to help people return.