President Bush made his second trip to the hurricane-battered Gulf Coast region on Monday.
Bush and the first lady landed in Baton Rouge, La., then moved on to Mississippi.
"So long as any life is in danger, we got work to do," the president said.
Meanwhile, New Orleans Mayor Ray Nagin said the estimated death toll could hit as high as 10,000, although only about 200 deaths have been confirmed.
Some residents of Jefferson Parish, west of New Orleans, were allowed to return home to view their properties but wouldn't be allowed to stay.
Former presidents Bush and Clinton announced the formation of the Bush-Clinton Katrina Fund to help hurricane victims in Lousiana, Mississippi and Alabama.
announced that it would donate $23 million to the fund.
Repairs have been completed to the 17th Street Canal breach, responsible for the posthurricane deluge into New Orleans, the Lousiana Department of Transportation announced during its midday briefing, the