New Orleans Mayor Ray Nagin suspends plans to begin repopulating the city due to a new threat from Tropical Storm Rita.
President Bush says he has "deep concern" about the possibility that New Orleans' levees could be breached again by another storm.
John Kerry and John Edwards criticize Bush for the federal response.
Americans have so far contributed about $923 million to charities helping hurricane victims.
The death toll rose to 973 on Monday, 736 from Louisiana alone.
Louisiana launches a federally funded program to temporarily hire up to 10,000 evacuees to work on the recovery effort.