President Bush says the U.S. government has launched the most massive relief effort in the nation's history to help victims of Hurricane Katrina.
Interviewed on ABC television Thursday, Mr. Bush said the top priority continues to be finding and rescuing thousands of people still stranded in the city of New Orleans and other hard-hit areas.
Rescue workers have begun transporting thousands of storm refugees from a New Orleans sports stadium to the city of Houston, 500 kilometers away. But the evacuation effort was put on hold Thursday after someone fired shots at helicopters being used in the operation.
Police have redeployed in New Orleans to stop increasingly aggressive looters, who have been stealing not only food and water but also items like television sets and guns.
President Bush said there should be zero tolerance for looters and other people who seek to take advantage of the disaster.
Rescue efforts extend to coastal areas of Mississippi, where Monday's storm destroyed thousands of homes and the area's popular casinos. Officials there say 110 people have died.
The mayor of New Orleans, Ray Nagin, says he expects the death toll from Katrina to rise into the thousands.